72 Facts That Most People Have No Reason To Know, Unless They Have A Very Specific Job

I’m a firm believer that everyone is smart, we just don’t all know the same things. Depending on your profession, your life experiences, and your interests, what you consider obvious might be mind-blowing to someone else. So to celebrate all of the niche information that people have floating around in their brains, one curious Reddit user posed the question, “What fact is common knowledge to people who work in your field but almost unknown to the rest of the population?” 

From insight about elevators to installing carpets to working as a barista, we hope you’ll learn something from the facts down below. Be sure to upvote the replies you would have never known otherwise, and if you’re looking to make a career change, perhaps you’ll feel inspired by some of these fun facts!


Drowning is silent. I pulled out a kid literally less than a foot away from a large group of adults and not one of them noticed that his head was totally submerged and that he was struggling.

Image credits: chachagirlsmom


As a chemist the thing that gets me every time is the, "I don't want chemicals in my......" statement.


Image credits: raethas


The best treatment for a child with anxiety is treating their parent’s anxiety.

Image credits: mmmnms


That if your IT Guy is not busy, he is doing a good job, not a bad one and you don't need to fire them

Image credits: HyruleJedi


Coffee shops spend more on milk than coffee.

Image credits: hotmesssketch


A corporate policy of requiring users to change their passwords every 90 days **does not** make your system more secure. It tends to actually make things less secure.

Image credits: kms2547


In Jewelry, a diamond is a luxury expense not an investment. Gold is the investment. If you try to sell your engagement ring you’ll get maybe 20% of what you initially paid for it. Jewellers can get diamonds for a fraction of what you paid for it.

Image credits: victorvanhux


There is no such thing as a perfectly functioning aircraft. Every plane you fly on has a multitude of maintenance issues, just not severe enough to affect safety of flight.

Image credits: Everything80sFan


One of my favorite facts about alcohol ads: In the US, nobody is allowed to be shown actually drinking the product. They can only be shown 'enjoying' it in ways that don't involve drinking it – so essentially holding it, pouring it, handing it to a friend, etc

Image credits: ragecage42


An elevator will go up to the top of the hoist instead of crash to the floor in most catastrophic failures due to the counter weights.

Image credits: mbjb1972


I work in live chat support. We can see what you type when you are chatting with us, before you send it.

Image credits: Springstof


Touching your fresh tattoo with your unwashed fingers is bad. It's absurd how many times we have to tell this to people.

Image credits: goddamnmike


Most people are not good at detecting lies, and consistently score no better than chance (50/50) when tested. The score goes up slightly when it's someone they know that they're talking to, but not much.

Ironically, most people rate themselves as very good at detecting lies, but they're wrong.

Image credits: DogsNotHumans


The first thing you do if you think your computer is being hacked is unplug it from the network (or disable the Wi-Fi).

Image credits: skribsbb


Turning your computer or phone off and on again will fix a solid 70-80% of all problems the device likely has.

Image credits: BleedingTeal


Nominal pipe diameters are not indicative of their actual diameter. So a 1" pipe is rarely actually 1" in either outside or inside diameter.

Why? I have no idea. But if you drill a hole of exact diameter and stick that pipe in there, you're going to have a bad time.

Image credits: lasteclipse


When you delete a file from your HD, only the information of how to reach these memory slots coherently is deleted. The raw information remains there until overwriten.

That's why companies (should) destroy their disks on decomission instead of just formatting them.

Image credits: Dr_Chemiramen


Hair is not alive. If your hair is damaged, you can't "fix" it. No matter what that bottle of conditioner tells you. Products that claim to fix damaged hair just deposit a coating of wax, simethicone, or dimethicone on the hair shaft that makes it look smooth. This build up will eventually make your hair limp and dull. The best solution to damaged hair is a haircut.

Image credits: Queengnpwdrgelatine


You would think all the heavily relied upon server infrastructures were super secure and highly redundant. Hahhahahahhaha


Nuclear power is pretty handily the safest and cleanest method of electricity generation. However, thanks to general misunderstanding and pop culture (looking at you, Simpsons), public trust in nuclear is lower than coal.


Potential cancer cells develop in the human body every day and our immune system efficiently kills them without any trouble and we just go on living our lives like nothing ever happened.

Image credits: rickbarr21


Just because a disabled child/person is non-verbal, that doesn’t necessarily mean they can’t understand everything you’re saying.
It’s crazy how often I have to tell my own staff to watch what they’re saying. These kids still get embarrassed or upset if you talk about the massive s**t they just took right in front of the whole class.


Most swiss cheeses (Gruyère, emmentaler, Appenzeller) are lactose-free, as well as any cheese that's been aged at least 2 years, like Parmigiano Reggiano or an aged gouda. I work at a cheese shop, and clients are usually surprised when I share that information with them. I wish more people with lactose intolerance knew about it!


In scoring for film, the orchestra/ensemble actually plays the music live as the movie is played behind them. It is recorded and synced

Edit: should have specified the conductor (who is usually the composer) stands facing the screen and has a small screen in front of them with different colored bars to indicate starting/stopping and pace, as well as other cues and insets. Composers have watched the film beforehand and are often frequent collaborators with certain directors.


I'm a sign language interpreter. This is based off the comments I get from the general hearing population:

1. We do not take care of or help the deaf person. We work for them same as we are working for you.
2. No, I'm not related to this deaf person. I'm not even friends with them.


Truckers leave extra space between themselves and the vehicle in front of them because if they are fully loaded they need the the extra space to be able to stop without flatten the someone. A truck can weigh the same as more than 50 small cars.

They don't leave the space, out of the goodness if their hearts, for a couple of cars to squeeze themselves into and create a potentially fatal situation!

Image credits: Vinterblad


If the menu has way too many choices that probably means the food is all frozen.


Heartworms are treatable for dogs, but not for cats.

Also, keep on top of your heartworm prevention for your dog; if they get heartworm but you can prove that they've been continually covered (which isn't difficult; the receipts are good enough, and your vet will have them in their database), then the heartworm prevention manufacturer will pay for the treatment.

Image credits: leprechronic


Not my current field, but when I worked at Starbucks not a lot of people understood that a larger espresso drink does not always = more caffeine. A tall drink has 1 shot, grande has 2, and a venti also has 2, unless it’s iced and then it gets a 3rd shot. So many times customers would order a grande latte and say “you know what, you’d better make that a venti, I can use the extra caffeine” when in fact the larger size is just more diluted with milk. If you are looking for more caffeine, a drip coffee is going to be the most bang for your buck.

Also, this seems really obvious, but a lot of people would get upset when they ordered a flavored coffee and saw that I would put syrup in it. No, coffee beans do not naturally come in caramel, vanilla, toffee nut, raspberry etc. flavor.

Image credits: babybokchoy1


"I'm sorry but there is nothing I can do"

Just because I work here it doesnt mean I can change the whole system, pricing or get back previous menu items.


Cracking joints does not cause arthritis. And the sound isn't bones cracking it's normally nitrogen gas escaping from your joint cavity.


Modern cars aren’t made weaker than old cars, or at least not in the way people would expect. A good example of this is if an old car hits a modern car and the modern car is crumpled to f**k and the old car looks like nothing happened. The cars nowadays aren’t ‘weaker’ or ‘made cheaper’, it’s a safety design and the reason this happens is so that if you have a collision the cars bodywork absorbs the energy of the impact and crumples, while you walk away from the crash relatively unharmed. An old car on the other hand doesn’t absorb the impact, which means the energy of the impact is felt by everyone inside the car instead, which is extremely dangerous and depending on the severity of the accident can badly injure or kill the occupants of the vehicle. Your car isn’t ‘cheaply made’, it’s an intentional safety design by the company that has saved so many people from broken bones, potential paralysis and death.


Virtually every piece of copper, aluminum, or steel you come across has been chopped to bits, refined, melted down and used to make whatever object it's a part of. Dozens, if not hundreds of times. Copper pipe? Probably started out as hundreds of different wires from various devices from around the world at one point.

Image credits: anon


Most 911 calls an ambulance receives on a daily basis are not remotely close to being emergencies.

Image credits: mega_lomein_iac


If you call 911 for something minor (flu-like symptoms, sprained ankle, etc.) you will usually be sent to the waiting room and triaged like every other walk in. You aren't saving yourself any time and we take great pleasure in watching your face when you realize the toe pain you've had for a week isn't a priority just because you took a ride in the boo boo bus.

On the flip side, depending on the system, EMS providers can do a lot to treat issues. Just because something is serious or even life threatening doesn't mean we load the patient, fire up the sirens, and zoom to the hospital (with a few exceptions like trauma and stroke). Rest assured, the 10-15 minutes we're in the back is being used to treat the problem and (hopefully) have you pretty much fixed by the time you get to the ER. We have a lot of medications and tools to use and it's safer for everyone to do as much as possible in the driveway or parking lot if we can. Please don't pound on the door yelling that we need to go when we're starting IVs, calculating doses, determining if we need advanced airways, etc.

Tl;Dr: EMS works very different than on TV (most of the time).

Image credits: Wilsonsj90


There is a surprising amount of infrastructure under your feet. You’d be surprised how much public utility runs underneath private property. Always call before you dig.

Image credits: zencanuck


The "essential" in essential oils doesn't mean it is *essential* to your body or health.

It basically means that it is the pure essence of that particular plant or flower.

So many people have taken this to mean that they are literally *essential* to our health and well being. It hurts my brain.


The toner in your printer is plastic being melted on to the paper.

Image credits: digggit


Neurodegenerative diseases (Alzheimer's,Parkinson,...) starts way before the first symptoms appears.

No one wake up suddenly one day with Alzheimer's. From actual data, it seems that the disease is rampant for 10-15 years before the first symptoms. Some research say that you can start identifying abnormalities 20+ years before the memory loss begin.

And it works for all neurodegenerative diseases AFAIK.

Image credits: Matrozi


When you write to your politician, he won't be reading your letter, he won't be writing the reply .. that's all done by staffers. All he does is "sign here".


Anyone can get an entry level IT job if you know how to use Google and have an aptitude for learning new things. Only when you get to the Analyst positions is it necessary to have a strong foundation of IT knowledge. And programming is something else entirely.


True A.I. is a LONG way away.

I'm a software engineer, and I work with a lot of algorithms. What's billed as "A.I." today isn't quite "Artificial Intelligence", it's just a bunch of advanced algorithms, some of which are capable of 'learning' things in a very strict/narrow scope. In other words, people (specially marketing) seem to use the terms 'machine learning' and 'artificial intelligence' interchangeably, when they shouldn't be. I guess I understand why, *Artificial Intelligence* sounds cooler, but really none of these things can actually make decisions on their own, which is a true benchmark of A.I.


There is a period of time every year that in the US, the Department of Transportation Pulls over any and every truck that they can. During this period many trucking companies take vacation time, as the potential hassle is not worth the money made during this time.


There is no difference between a violin and a fiddle other than how you play it.

Image credits: videcortuus


The lighter the roast of coffee, generally the more caffeine found within the bean. I know a ton of people who drink dark roast mistakenly thinking they’re getting their morning buzz going. Sorry to break it to you..


Based on the number of calls I get about this a week, it would have to be that the water company does not provide hot water to your house. I just don't understand how people have never heard of or have seen their hot water heater.


Civil Engineer here. The production of cement (the stuff that you mix with water to get concrete) accounts for A LOT of the worlds CO2 emissions. There are estimations saying it accounts for up to 8% of the world wide CO2 production. Thats more than global air traffic produces.


Most PhD programs don't have a fixed timeline in the same way other degree programs do. In other words, unlike undergraduates, most PhD students don't know their expected graduation date until they're almost complete.

So stop asking PhD students when they will be graduating.


“Military grade” does NOT mean it’s awesome.


You cannot go from having black hair to silver or platinum blonde in one sitting. It takes multiple and 9 times out of 10, your hair is fried beyond repair by the end of it. Kim Kardashian or whoever you pinned on your pinterest page or Instagram is wearing a wig.


The President doesn't control the Economy.

A shocking theory for most people I talk to.


When public play structures are being evaluated, the evaluator brings two size paddles, one which is equal to the average size of a newborn's head, and one that equal to the largest average size of a child under 10. They then stick the paddles in all crevices of the play structure. If the smaller one (the head) can get through, the bigger one (body) must also be able to, otherwise the structure won’t pass inspection


Mathematics is closer to philosophy than it is to anything else in STEM.


diamonds are fairly common. white and colourless diamonds are scarce. 90% of diamonds are usually yellow or brown.

only diamonds that are near white, and near-flawless under 10X magnification are used in jewelry, the rest are ground down and used in tools (drill-bits, saw-blades etc)


No matter how secure you think your house and valuables are, if someone wants to get in they are for sure going to be able to do so.

Tldr:home security is a detterence


If you stick your eardrum with an object, you will start to cough. This happens because the nerves interconnect (n. Vagus).

I hope this information helps you in future battles.


How many people actually drive a car before it gets to the dealer.


You don’t defibrillate asystole (flatline cardiac rhythm) like they do on TV. It’s a non-shockable rhythm.


Doubling the dose of a drug does not double the effect. Likewise, a child should not be given the same dose per kg bodyweight as an adult.


Low flow toilets often exaggerate minor sewer problems. If solid waste has to get over an obstacle, like a rootball or a belly in the pipe, a low flow toilet won't give it the push it needs, and in the worst case scenario, cause a backup.


I worked as an insurance adjuster, most people have no idea what homeowner's insurance actually does. Here is a very simple guide to understanding what is covered by homeowners insurance:

> A sudden and one-time occurrence

While there are some exceptions to this, understanding those few words will help you understand 95% of what is and is not covered by your policy.

* Note: My experience applies to US insurance only

Image credits: Dicktremain


Children behave differently at home than they do at school.

Seriously, teachers have no reason to lie about your child misbehaving. Logging behavior and initiating a less-than-positive exchange creates more work for us. Why would we lie to create more work for ourselves?


It really does help us at the library when you don't reshelve your own materials.

(Not because we don't trust you to know where they're supposed to go, but because if you put it away yourself, we can't keep track of the fact that someone looked at it, which is useful information for us to have.)


In designing 3D games, many programmers, even in big gaming companies, still have a hell of trouble with colliders (making it so the player doesn't fall through the floor/wall through walls etc.) Everything should work correctly, but nooooo. The solution? God knows. We all just layer dozens of colliders on top of eachother and hope for the best.
Why do you think there are so many walking through corner glitches?


That a lot of truck driver especially out west are atleast partially distracted just to keep themselves from falling asleep behind the wheel. Some of us have YouTube or Netflix just for noise that's not talk radio, are reaching into their cooler for a snack or drink with one hand and lighting a cigarette with the other all while steering with their knees. Others are talking on the phone while trying to keep their dog or cat out of their lap while also brushing their teeth and reading a map or GPS looking for a place to pull off for their break. And anyone who is a trucker that says they have never done any of that is either brand new or is a liar. We do pay a lot more attention when in the mountains or in populate area though


Your eyes and mouth don't stay shut when you're dead. Somebody (me) has to shut them to make a deceased person look more presentable.


No, you shouldn’t refuse a raise because it’ll put you into a higher tax bracket.

It’s a progressive system; you don’t get taxed based on your total salary for the year, rather it progressively get taxed. (Dollar 50000 gets taxed higher than dollar 1000)


Most herbal supplements can and will give you adverse/side effects when mixed with other medications. ALWAYS tell your doctor everything you're taking.


If you're putting in new carpet, always go top shelf with the pad. The increase in cost is neglible and the upgrade to feel, usability and endurance of the rug on top will be way better dollar to value ratio than spending on the carpet itself. 8 lb memory foam is maybe 2 bucks a yard more than trash apartment grade stuff but 10 times better underfoot.

Go for the cheapest carpet you can stand (remember, you aren't going to be running your fingers through your house's carpet for more than 3 days after it's installed) and put the best damn pad money can buy under it. You'll spend less and it'll feel like you bought 50 dollar a yard carpet.


Former field as I'm still learning my current one, but auto glass is no joke.

Tons of your car's features are directly connected to your windshield. They're also a pretty important safety feature in your vehicle. Unlike your side and rear windows, which are typically tempered glass (also, in part, for safety reasons), windshields are laminated which is why they crack instead of shattering unless something really drastic happens to it. Also, because it's laminated, it can crack all the way from side to side and you're still safe. Just not from Johnny Law because he might give you a ticket.

For most makes, most of those new safety features like lane departure warning and forward collision alert are on sensors that work through the glass. Rain sensors, condensation sensors (if your AC automatically kicks on), auto dimming mirrors....they all have different brackets and frit cutouts to allow them to work properly.

Those black dots that drop down in the center by the rearview mirror that most people think is an antenna? Nope. Just an extra sun shade that's supposed to help block the sun in between your visors.

Also, fun fact, if you ever need to break a window in your car for whatever reason, the smaller pieces of glass are often the most expensive piece of glass on your vehicle. Go for a door tempered door glass.

Knowledge to some, but after almost a decade in auto glass, I learned that most people have zero clue when it comes to their auto glass.


More people die in lifeboat drills than they do in any other marine incidents.


“Organic” foods aren’t necessarily grown without chemicals. There’s a ton of organic label pesticides out there, many of which are just as toxic as their synthetic counterparts.

Older Post Newer Post