I used to think that everyone turned a certain age, and you could take your teeth out of your mouth.
(Because I always saw my grandparents' teeth in water at night when we visited)
A childhood belief about getting older

others believed things like this
- I used to believe that if I didn't brush my teeth at night, ants would crawl into my mouth and eat my teeth.Anon
- I used to believe that eating burnt toast would make your teeth whiter and would brush your teeth for you.— Natasha
- Until I was about 8 I believed that your back teeth keep growing in until you have a full circle of teeth.Anon
- When I was very young, I assumed that false teeth were taken from dead people's teethAnon
- Until I was around 8 or 9 years old, I thought dentists took your teeth out and replaced them with new teeth.— Verapamilo
- when I was a kid. I used to believe hens had teeth.— lév michot