I used to believe that the days marked on the calendar with a slash dividing two days were half days so that about mid day it would switch to a week ahead then back again for the next day.
A childhood belief about general

others believed things like this
- I thought that "tomorrow" was one of the days of the week— Frank
- I once refused to believe in Thursday. I'd heard there were seven days in a week, but could only name six.Anon
- I always thought that after 1999 it would be 1990 again, but with different months and days of the week
— optional - back in the days i thought the world was black and white like in the pictures— compaq
- i used to believe that if you got barked at by a dog you would die in 45 days— woza
- I use to believe that peeing was bad for your body, and it should only be done once per 3 days— Master P