In the song "Groovin" by the Rascals, there is a part at the end where they sing "You and me, endlessly, groovin"
I thought they were saying "You and me and Leslie, groovin" I couldn't figure out who this Leslie chick was. My older brother claimed it was a child by a previous marriage and I believed him.
A childhood belief about misheard lyrics

others believed things like this
- when i was really young, i couldn't figure out why i can't get older than my older sister.— angela
- I thought Buckwheat from "The Little Rascals" (1994) was a girl because he had long hair!— Molly
- i though that the man and woman couldn't really have babies until marriage,lmao,what a stupid person i was— what a stupid
- I thought that singer/songwriter was spelled this way: sing-a-song-writer...Anon
- My older brother told me that everytime you sneezed your lungs would bleed. I believed this until I was 21!— Gem
- I used to believe that "euthenasia" was "youth in Asia", and I couldn't figure why that was A Bad Thing.— Kellye