I used to believe that grown ups never told dirty jokes or cursed. I thought only kids like I was did that. Then I found out in amazement that adults told dirty jokes as well.
A childhood belief about swearing

others believed things like this
- When I was a child I used to believe that stand up pianos actually told jokes as well as playing music.— L MAN
- when i was younger i thought ac/dc's dirty deeds (done dirt cheap), was dirty knees and the thunder cheeks.— S
- When I was a kid I thought oral sex was when adults "talked dirty".— Chris
- a friend thought that the song "dirty deeds done dirt cheap" was saying "dirty deeds dunderchief"— dubs
- up until i was like 13 i thought that oral sex was phone sex and dirty talk.— RoNiBoB311
- When I was little, I thought that Water Towers were full of dirty laundry. Why? I dont know.Anon