“I was baking a cake in my dorm for my 19th birthday. My friends were running around and being loud so I yelled at them to stop because I didn’t want them to ruin the cake. They looked at me like I had two heads so I had to explain that my siblings and I were always taught that making loud noises or running around a kitchen when something was baking would make it fall.

I was surprised they had never learned that baking rule Yeah turns out that was made up to stop kids from running and being loud for a couple hours when baking was being done. I called my mom up to ask her about it and both she and my grandma were just as shocked as I was to find out it’s a myth, so apparently, at least 3 generations have believed and followed that rule.” - rakedleaves

“My mother used to feed me 'dark green lettuce' as salads, I loved it even when I was a kid. I think I was 17 and I had a friend over for dinner, asked my mom for seconds of dark green lettuce. Friend looks at me like I'm a fucking idiot, "Uh, you mean spinach?"

“Not me, but in college my buddy asked me how to spell "smorning" because his phone didn't recognize it as a word. He then goes on to say "you know, like 'the smorning'". I ask, "do you mean 'this morning??” - InfernoCBR

“I thought Robins (the birds) came out of hibernation at Christmas time because that's when you see them on cards and stuff in the UK. I did not realise for an verrrry long time that you in fact see them all the time, like normal birds.” - bos_well_

“I was in my mid 30s before I realized that the 'turn your head' part of 'turn your head and cough' was so that you didn't cough on the damned doctor. I always thought it must've flexed some particular muscle or something, I don't know. To my credit, I am a man and I don't think I've ever had to do that.” - RaceCeeDeeCee

“One day I had a lightbulb moment. “Pickling is a process! You can pickle anything. SO WHAT ARE PICKLES?!?” I was gonna blow so many minds with this question. Turns out, it’s cucumbers. And everyone on the planet knew that, except me.” - Goatpuppy

“For years I had been removing toast from the toaster by sticking a butter knife in and picking it out. It wasn't until I was 20 that my girlfriend freaked out when I started doing it that I learned metal in toaster = bad. Guess I'd been pretty lucky…” - shallowwaters

“Not me, but my father once stole into the woods during a family camping trip and put marshmallows on a bush, so it looked like they grew on it. My sister made it to post secondary horticulture before she wised up.” - NikthePieEater

“I always thought the term, "the coast is clear"...was, "the ghost is clear" (transparent).” - Royal_Elderberry

“My great-grandfather had half a pinkie on his left hand and always said it was because he liked to use it to sop up leftover pancake syrup and had worn it down to a nub. This made sense to me because I'd seen him do that plenty of times. I was so embarrassed to be in college before I realized that was ridiculous and finally asked him what really happened. In reality, he and my uncle had been working in their blacksmith shop, and my uncle accidentally brought a sledgehammer down on his pinkie. He didn't want to traumatize me with the truth as a kid, but by the time I asked, I was more than old enough to handle it.” - EducatedOwlAthena

“That Alaska isn’t an island with a weirdly straight border” - PeachyMazikeen

“It only recently occured to me, I my fifth decade, that "Watch where you're going!" means "Look in the direction you are walking," and it's not just something to say to someone who bumps into you.” - wdr1977

“I didn’t realize the handicap sign was a person in a wheelchair for a long time. I had always thought it was just a neat little symbol, kind of like a treble clef.” - karate_jones

“As a kid I used to think the Black Market was an actual place like a bazaar where all the criminals would regularly meet up” - PM_ME_FREE_STUFF_PLS

“When I was 4 or 5 my mother brought me home a balloon one day. Plain blue balloon with helium. I accidentally let it go and it flew away. Being little, I was devastated. Later that night she comes back from somewhere and tells me she was at the gas station and miraculously, my balloon just came floating by.

Being a kid I was thrilled and totally believed it. So fast forward 20+ years. I’m on a date and we stop to get gas and we see a balloon floating by the gas station. Probably hadn’t thought of that story again in all that time. So I start telling my date the story about how I had a balloon fly away and then my mother found the very same balloon at a gas station and then as I’m saying it out loud I realize (too late to not look like an idiot) that of course, it wasn’t the same freaking balloon. I’ve never seen someone laugh so hard.” - Bonzi777

“I truly believed that for the longest time that hair grew from the ends of the strands, not from the scalp. When I was 13 I asked my friend who had dyed her hair what she was going to do when the ends grew her natural colour. Didn’t hear the end of it. My stupidity still pains me to this day.” - oreo_2005

“I thought until the age of about 21 that when companies had "Est" next to their name, it was estimated that companies were started around that time. It was only when I voiced my disgust profoundly to my then-partner that it was ridiculous that no one knew when these companies were formed, and why were they all estimated?! She just stared at me blankly for a moment and just went: "Established" Penny dropped real hard.” - Wolfy-1993

“That little thing that dangles at the back of your throat isn’t your tonsils.” - spriest14

“I was 23 when I learned I was allergic to apples. Someone was complaining about their throat closing up after smoking, and I responded with “oh yeah like when you eat an apple?” You can imagine how the conversation went from there.” - CaptCapsize

“Depends what you consider a child I suppose. But in my mid 20s I moved up the food chain from server to bartender at the restaurant I worked at. Some one order a Roman Coke. I didn't know what was in a Roman Coke so I told him so and but that I would figure it out. I figured out that what I had been understanding as a Roman Coke my whole drinking life, was in fact a Rum & Coke...that, I knew how to make!” - uuonderlust

“A friend of mine had a mom that would make sure there was an inch of room for his feet to grow whenever he got new shoes as a kid. He was in his twenties and trying on new shoes, and asked the salesperson if there was room at the tip. They looked up at him like he had a dick growing out of his forehead and said, "You don't need room, you're done growing." Oof.” - RonanTheBarbarian

“A few years ago I was searching for different classical pieces in Spotify, getting frustrated that every version Spotify had of works by composers like Beethoven and Bach were "covers" performed by modern orchestras. My idiot brain was looking for original recordings from the 18th Century until it finally realized how dumb that was.” - DisraeliEers

“Not me, but a friend of mine didn't learn that Martin Luther and Martin Luther King, Jr weren't the same person until college.” - el_drosophilosopher

“Don’t add dish soap to the dishwasher. Found that one out at 26. I swear it’s only because I grew up washing dishes by hand. Had a fun time cleaning that mistake.” - Fried_puri