#1
Vaccines are safe and effective.

Image credits: Bushy_Wampa_Pussy
#2
Not everyone's disability is visible. Just because someone parks in a handicap spot then gets out and walks in without you being able to tell why they're handicapped doesn't mean they don't deserve that placard.

Image credits: phyxiusone
#3
The on-ramp is for accelerating to highway speeds *before* you reach the highway.

Image credits: Jak03e
In an academic environment, common knowledge refers to “information generally known to an educated reader, such as widely known facts and dates, and, more rarely, ideas or language,” according to Harvard University.
This information shouldn’t need a citation backing it up for the average educated reader to understand it. “Widely known scientific and historical facts—such as the molecular structure of water (H2O), or that Andrew Jackson was the seventh president of the United States—generally count as common knowledge. You can include such facts in your writing without citation and without fear of committing plagiarism,” the educational institution further instructs.
#4
Vaccinations do not cause autism and never did.

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#5
*Should have* / *would have* / *could have* = the contractions *should’ve* / *would’ve* / *could’ve*
It’s not *should of* / *would of* / *could of* - those word combos make no grammatical sense.
#6
The difference between an opinion and a fact.
Knowing whether something is common knowledge can be tricky. Therefore, Scribbr, a company that provides a range of academic services, suggests asking yourself a few questions before assuming something is common knowledge. Like, for example, ‘Who is my audience, and what can I assume they know?’ In case your audience has knowledge in the same field as you, you probably can get away with assuming they know more than an average person.
#7
Basic Geography.
Not being able to point out Turkmenistan on a map is one thing.
Not being able to point out the Pacific Ocean on a map is another.

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#8
How to use a d**n roundabout, apparently.

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#9
That the IRS will never request payment via iTunes gift cards.
If you think your addressee might be surprised by the information you present or question its accuracy, then it probably isn’t common knowledge. Another indicator of information not being known to everyone is if it can’t be easily verified with a quick Google search. No piece of common knowledge has to be dug out of the depths of the internet or other databases.
#10
Africa is NOT a country, its a continent.

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#11
That you shouldn’t be rude to customer service or the cashier cuz it’s not their fault that the item is expensive.

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#12
If your wipers are on, your headlights should be on.

Image credits: anon
Knowing when a piece of information is common knowledge or not isn’t only useful in academic environments but also in everyday life. It can help you better communicate with others if you aren’t assuming they know everything you know. It’s easy to fall into this assumption trap, as we can possess a cognitive bias called ‘knowledge curse’ that makes it difficult for us to imagine others not knowing something we know and have learned.
#13
That there are no tigers in Africa. I was on safari in Tanzania and two others in the truck were discussing how excited they would be to see tigers. I told them there weren't any and they looked all disbelieving and crestfallen, like I was spoiling their fun. They had to check with the guide.

Image credits: 4ar0n-Aaron
#14
That whales are mammals that used to be on land but evolved to swim instead.
I had an art teacher that just didn't believe me when I told her that they're not fish.
#15
Correlation does not equal causation.
Ironically, the curse of knowledge makes it difficult for people to share their knowledge because they fail to empathize with their level of knowledge. It significantly affects how information is communicated, which can be an issue for educators and experts in particular. They might struggle to convey complex concepts to their audience because they struggle to imagine what it’s like for others not to have the depth of knowledge they do.
#16
Gambling at a casino will most likely result in losing money.

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#17
That antibiotics k**l bacteria, but won't do anything against viruses. Everyone has the idea that if you get a cold, you see your doctor and get antibiotics. Take some acitaminophen/paracetamol and ibuprofen, and stay away from other humans for a while!

Image credits: Slidingscale
#18
That using your blinker while driving a motor vehicle is helpful to indicate to other drivers where your dumb a*s may be going.
Fortunately, the curse of knowledge can be overcome. The first step toward it is to embrace empathy. Practicing perspective-taking and putting ourselves in others’ shoes can help us gauge how to communicate and explain information to others better. Next is simplifying and clarifying the way we communicate with others. Complex ideas should be broken down into smaller, more manageable chunks and illustrated with examples.
#19
Just because eggs are sold in the dairy section doesn’t make them a dairy product.
I’ve heard people say they don’t eat eggs because they don’t eat dairy.

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#20
That narwhals exist/are real. People have thought that I was trolling them by talking about a mythical unicorn-whale.

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#21
Tax brackets. You won't end up paying more in taxes than the extra income if you go up a bracket. Only the income ABOVE the cutoff is taxed at the higher rate, not your total income.
I had to explain this to a guy in his sixties, literal years away from retirement.

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To ensure that the communicated information was clear, the speaker should also encourage questions and feedback from their audience. If there are any knowledge gaps left, the person can then clarify the information, providing the missing puzzle pieces. Remember, clear, concise, and accessible communication can bridge people’s knowledge levels, which can result in an environment where information, inclusivity, and innovation can thrive.
#22
The passing lane is for PASSING, not for your leisurely drive under the speed limit.
#23
How to stay in one's own lane when turning from one street to another.

Image credits: Scrappy_Larue
#24
Don't pet service dogs. I used to think everyone knew this, until I got one.
Don't pet them, talk to them, make kissy noises, bark at them (grown a*s adults barking at service dogs is shockingly common), whistle, clap, none of that s**t. Do not do anything to deliberately draw the dog's attention.
If they are distracted, the handler could get hurt or even die. Not exaggerating. If a medical alert dog misses an impending medical emergency, the person doesn't have time to get into a safe position or take rescue medications. If they have a seizure or slip into a diabetic coma or something because you distracted their service dog *it is your fault.*.
#25
That the vast majority of telecommunications traffic between countries is carried via undersea fiber optic cables.

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#26
That a lot of people didn't know what a tariff was.
#27
I work in IT and I’m constantly helping people who:
•Don’t know what the Windows key is.
•Don’t know Internet Explorer/Chrome/Firefox are web browsers.
•Making your password your name is a really poor choice.

Image credits: Bar_Har
#28
You don't need a rooster for chickens to lay eggs.
#29
Alcohol has calories.
I had to be the one to tell my friend when she was in her mid-20s that the vodka she loved has calories. She was so shocked and said, "What!! I thought since it was clear like water it didn't have any calories.".

Image credits: -eDgAR-
#30
Everyone seems to get close to wild animals for pictures and think it’s ok. We are not all one with nature and animals like their space and don’t trust you.
#31
Taking out your credit/debit card / cash out before you are asked to by the cashier / checkout staff saves time for everyone, rather than looking shocked that you have to pay for your shopping.
#32
That WWI and WWII were real and separate events that really happened, not just movies. Talking to her was deeply painful.
#33
That something being "organic" doesn't mean it is extremely healthy.
#34
That other planets are visible from Earth. And the sun is also a star.

Image credits: anothersundayx
#35
Washing your hands after using the toilet.
#36
The Guinness book of world records is actually made by the beer company. It started out as something they gave for free to pubs who stocked guiness to help resolve pub bets between friends.
#37
That crypto is not regulated asset like a stock, bond or CD.
#38
That all cows are female. Male animals don't have milk-producing udders, *Sean*. The male version of a cow is called a bull.
Incidentally, I recently learned there's no common genderless word for a member of that species. There's "cattle" for a group of them, but nothing for an individual.
#39
That birth control is not 100% effective, even an IUD. Even your tubes being tied or a vasectomy.
THAT BIRTH CONTROL DOES NOT PROTECT FROM STI'S.
Yes you can get pregnant having s*x on your monthly.
No formula is not better for the baby than breast milk.
And my mother in-law takes the cake: Yes, women do in fact create and birth boys.
(To clarify - we were driving one day and she very seriously and flat out said to me that she was confused how she made a son because she's a woman.).
#40
That properties in monopoly go up for auction if the person who landed on it doesn't want to or can't afford to buy it.
#41
A.D. means Anno Domini. not After Death.
#42
Basic principles of finance (budgeting, interest, debt, saving, etc).
#43
A surprising number of people don't realize you SHOULD NOT flush hygienic products down the toilet. If it doesn't eventually back up your own pipes it will create massive blockages in the public sewer. I had to explain this to a friend in her mid-20's, I was like "Why do you think there's little trash cans on the wall of every women's stall!?!?"
#44
When my 50 year old sister was asking how the stars can reflect sunlight at night when the earth should be blocking it.
I have never recovered from that question.
P.S. I study astrophysics as a hobby my entire life.
#45
Last year i was walking home with a friend at night when my friend says " woa look at that star, it shines brighter then the rest" so i say, "yeah, it is probably a planet". He refused to belive me when i said you can actually se other planets from earth. The next day he would not stop talking about it. Apparantly he had been googling it all night.
#46
I've seen some Jimmy Kimmel skits where people are asked where certain well-known places in the world are, like "Where is Australia? Where is Africa?" And they literally can't point to them on a map; or they think Africa is a country. I just don't understand how people don't know this stuff.
#47
A "screen saver" is the animation (or blankness) that pops up on your computer when you don't use it for a while, to **save** your **screen** from getting burned-in.
The background picture that wallpapers your desktop is the "wallpaper".
#48
You have to look at the toilet paper after wiping to determine how much p*o is left on your butt.
You also have to touch your b******e with the paper.
No, it is not "gay" to clean yourself.
#49
Ducks can fly and have water proof feathers.
#50
That margarine isn’t butter...it hurts my soul when people refer to margarine as butter.
#51
That generic products are generally made in the same factory as the namebrand.
#52
The flu is not just another cold, and you can’t use the words interchangeably. Many people have never had the flu, or felt that unwell. The flu will knock you on your a*s.
#53
There is gravity everywhere. On the ISS the gravity is only a bit less than it is on the surface of the earth. The reason the astronauts float around isn’t because there’s no gravity; it’s because they’re in a state of free fall.
#54
"For all intents and purposes" being b*********d into "For all intensive purposes".
#55
"Righty tighty, lefty loosy". A 35 year old man had never heard of it.
#56
Ponies are not baby horses. Just like chihuahuas are not Rottweiler puppies.
#57
You're allowed to start a sentence, even a paragraph, with a conjunction for the sake of emphasis.
I've had multiple people try to correct that, and then I'll show it to a professor and be like "This is grammatically correct, right?" and they'll say "Of course.".
#58
Money disappears when you spend it it’s not magic.
#59
Washing your hands often makes your hands more dry.
#60
North is a fixed direction, not just the way you happen to be facing at any given moment.
#61
There are 5 oceans. People around my age and older (25+) only seem to think there are 4. Atlantic, Pacific, Indian, and Arctic. Well guess what? In the year 2000 they decided they were gonna name another ocean. So the Southern Ocean is the 5th ocean.
The ocean that no one told us about.
#62
“Hey mom, who was the first man on the moon?”
“Tom Hanks.”.
#63
Using your turn signal.
#64
My friend had his address written on a a keychain with his house key. I explained to him that this was a bad idea and everyone around me thought I was a wizard.
#65
Ctrl C - Ctrl V.
#66
That you can wash blood with saliva.
#67
If you're entering a venue that requires a ticket to be scanned for entry, someone without a scanner can't let you enter.
#68
Don't p**s on a jellyfish sting.
Edit: If you don't know where I got this from, people trusted that episode of *Friends* as knowledge. Also, you are supposed to do it for a Portuguese Man o' War as a second option if you don't have vinegar or something else. Also, a Man o' War is not a type of jellyfish. That should help explain what I mean.
**Extra: Don't p**s on a jellyfish, sting.**.
#69
That the US does indeed have a hurricane season.
#70
That you had to finish antibiotics even if you feel better or you risk bacteria coming back stronger and more resistant. Glad I warned my friend, didn't want her to get even sicker or cause a pandemic.
#71
The earth is round.
#72
That in order for an aspirin to help 'save your life' while having a heart attack, you need to chew it.
#73
A girl at my work was talking about her bucket list. Near the top was "I want to visit all the ancient wonders of the world."
She was *crushed* when I told her all but one have been destroyed.
#74
You are meant to do the tutorial in games.
#75
When people say “drink the kool aid,” and don’t know where the expression came from.
#76
When I mentioned wanting a hard-drink as opposed to a soft-drink. They did not know the correlation between alcoholic and non-alcoholic beverages.
#77
That in the American tax system, getting a raise and going into the next tax bracket will not result in less income for you.
Edit: To clarify, I'm not talking about situations where a benefits cliff might exist.
#78
The difference between than and then. I seriously thought that when I heard people using the wrong one it was just due to their accent.
#79
How to use your debit/credit card at a checkout.
#80
Alaska and Hawaii are not part of the contiguous US.
A person I knew thought they were both in the southwestern US because that where they were always placed on the map.
They thought Socal was north of Alaska...