i used to believe (very logically) that there were only 365 people in the world. that way, everyone got their very own birthday that they didn't have to share. (i guess i didn't consider twins, huh?)
A childhood belief about birthdays

others believed things like this
- I used to believe that on your birthday, you didn't advance to your next age until you ate your birthday cake.— Casi
- My Aunt used to tell me that if I didn't share, I would turn into a crow.— Peter
- I used to believe that every country in the world had the same time. Guess I didn't consider time zones eh?— what are time zones again
- I thought you didn't have to go to school when it was your birthday.— M_1
- I used to believe that on your birthday everybody would worship you! (I guess I was wrong).— supergirl
- i used to think that if i didn't celebrate my birthday each year my younger sister would catch up with me— q