You might not know how the female menstrual cycle works or you might not know that Puerto Rico is actually a part of the United States.
You might not know how to tie your shoes properly or you might not know that the interesting term you learned about when you were a child is actually a racist one (and not a term of endearment).
You don't know what you don't know, as we were so clearly reminded after Redditor seanmashitoshi asked the online community:
"What is something you learned embarrassingly late?"
"I tied my shoes..."
"I tied my shoes a very different way until I was in middle school. Our teacher had us all write down exactly how to tie your shoes, then had one of us go up and try to follow the directions exactly as how they were written."
"Everyone laughed when they got to my directions."
"That Alaska..."
"That Alaska was not an island."
"In grade school, I only ever saw pictures of it in the textbooks next to a picture of America, boxed away in a corner next to Hawaii so I just assumed it was also an island. I was over the age of 20 when I was finally corrected."
"That Filipinos..."
"That Filipinos are from the Philippines. One starts with a F and one with a P, never thought to put two and two together until i was like 13."
"I didn't know..."
"I didn't know until I was like 17 that women's periods were a constant, slow leak. I always just assumed it was like pee where you could hold it in, and release it all at once."
"That the term..."
"That the term "chinky eye" was not a term of endearment and that it is a derogatory term used against Asians."
"In middle school we all did high, tight pony tails trying to pull up our eyes to be cute. I never associated the two."
"Imagine my horror when I realized it was a slur- AS I "complimented an Asian on their super cute chinky eyes. It didn't click until that moment. This was in my 30s."
"That men and women..."
"That men and women have the same number of ribs. Thanks, Bible belt."
"As a child..."
"As a child, I was absolutely obsessed with Veggietales, watched the VHS's all the time."
"It was maybe 2.5/3 years ago I realized Veggietales is a Christian show."
"The worst part, my favorite episode hands down was the one with the chocolate bunny factory, which looking back is part anti materialism moral and part false idol fable. But here's the thing..."
"For the uninitiated, the bunny episode is the one where, despite my baffling ability to totally tune it out, the day gets saved when Jesus literally shows up."
"I was a dense kid."
"I never saw..."
"I never saw Dachshund spelled and pronounced at the same time until I was watching a show a few years back. I always thought it was pronounced Dutch hound and "doxen" was just a nickname like "weenie dog."
"I was 32..."
"I was 32 when I learned that coral was an animal."
"I always assumed it was an undersea plant. I didn't take biology."
"When I was little..."
Giphy"When I was little and they declassified Pluto as a planet my brother told me it was because Pluto imploded and was only the size of a basketball now so it is no longer a planet."
"I was TWENTY YEARS OLD when I was talking to my husband about when Pluto imploded and stopped being a planet when we were kids when he was like "WTF are you talking about?" And I realized I had been living my whole life believing this lie."
"I still feel like an idiot."
Better late than never for most of these!
Do you have similar experiences to share? Let us know in the comments below.
@ZoeyCatBell
@twinkb23/Bluesky
@EvralW88115/X
@shanikom/Bluesky 
@Milezla1/X
@scotiasheppard/Bluesky
@greyreptilian/Bluesky 
@rickcity/Bluesky 
@kristengough/X
@Placidopv/X
@tylerblack32/X