I used to believe that "half an hour" and "an hour and a half" were the same thing, just different ways of saying it, until the third grade when I got into an argument with my friend about it. She asked the teacher, which (of course) proved me wrong and I felt really embarrassed.
A childhood belief about general

others believed things like this
- An hour and a half is exactly the same as half an hourAnon
- I used to believe that all songs were exactly a half-hour long.— Brian
- I thought the big hand was for the hour and the smaller one was for the minutes until i was in third grade.— Time Challenged
- I used to believe that your belly button was what held your top half to your bottom half...— Debelouwho
- I used to believe that a quarter after the hour was 25 minutes after the hour because 25 cents = a quarter.— Marni
- You had to wait an hour after eating ANYTHING, even one M&M, before swimming. Anon