I used to mishear the Eric Clapton song "Cocaine". Listen how the meaning changes for the want of just one word: "If you want to hang out, you've got to take her out, okay/ If you want to get down, down on the ground, okay/ She don't lie, she don't lie, she don't lie... okay.
I knew about sex by then, so I thought it was about a girl, and that it was okay with her daddy to date her because "she don't lie".
A childhood belief about misheard lyrics

others believed things like this
- I used to think Jimi Hendrix was white, and Eric Clapton was black.— Steve
- I used to think the song "Hang on sloopy" was "hang on snoopy"— gina
- I thought cocaine and marijuana were the same thing.Anon
- when in was little i used to think that cocaine was sugar until i found out what it was— jamie dulake
- I thought ground beef was the meat they scraped off the ground at the slaughterhouse. Yuck.Anon
- When I was little, I thought that you had to marry someone who was born on the same date as you.— Lauren