I used to believe that there were no thieves in the real world. People just invented them so that comic books would have a more interesting plot. :)
A childhood belief about criminals

others believed things like this
- I used to believe that the whole world was in black and white before colour TV was invented...— Robsa
- I use to believe that the world was black and white until color was invented for television.Anon
- I used to believe that until gravity was invented, people used to just float around!— Meg
- When I was little, I used to believe that my Barbie's would come to life while I was asleep to plot my death!— Kimbre
- I used to think that the starwars weekly comic wasn't very strong.. duh.— TAM
- I used to believe that when I went to sleep, my Barbie dolls would make out and plot to kill me.— ClaireRat