A place to share things you learned the hard way.
On my eleventh birthday, my friend once told me he swallowed a Fruit Pastille without ever chewing it. On the way back from school, I had opened a gift I got from a distant relative, which turned out to be a box of Malteasers. Being the competitive 11-year-old I was, I tried to swallow a Malteaser without chewing it. However, my hubris got the better of me, so I began choking on my Malteaser and very nearly died. As my vision began to fade, my mother patted me on the back, not reallising I could have died had she not intervened. The Malteaser in my throat got forcefully ejected back out through my mouth and bounced off a window and landed on the dirty carpet in the car.
I went to the Ladies Restroom at a mall because I had to pee. While I was waiting for one of the stalls to open, I saw a lady changing her baby's diaper while the baby was standing up. Because of that, I now know what a male baby's "Little Pringle/Ding Dong/Wiener/Exactly what you'd expect" looks like. I learned it the hard way.