I used to think that a "mafia" and a "gang" were the same thing except for what gender made up each one: A mafia being for girls, and a gang being for boys. Since the word "mafia" sounds like a girls' name, while the word "gang" sounds less feminine and therefore more like a boy's name, this belief made perfect sense to me and i believed it until middle school.
A childhood belief about criminals

others believed things like this
- I thought if I went around yelling "The Mafia sucks!" someone from the Mafia would kill me— Mexicrat
- When I was a little kid. I thought that police officers were a gang of mean people who bullied others.— LOOL
- I used to believe that the twinkling of the stars made the sounds that crickets made.Anon
- I used to believe the Beastie Boys were a boy band. Well, the name sounds similar to Backstreet Boys!Anon
- I thought that the difference between girls and boys was that girls have teeth.
Anon - that cats were only girls and dogs were only boys. I definetly didn't get the whole reproducing thing yet.— Jamie