I used to believe part of the lyrics to Fall Out Boy's "Centuries" went:
"You look so pretty, but your gun's so soon."
When, really, it's
"You look so pretty, but YOU'RE GONE so soon."
A childhood belief about misheard lyrics

others believed things like this
- I USED TO BELIEVE THAT IF YOU STARED AT A PERSON, THEY COULD NOT TELL YOU WERE STARING AT THEM. PRETTY STUPIDAnon
- i use to think boy geroge from the culture club was a pretty woman.— toe
- My mom used to think "preschool" was called "pretty school" until a few years later.— Molly
- Looking back at it, the belief that dogs eat cats is a pretty funny idea. I used to believe it myself.Anon
- i could swear eleventeen was a number for the longest time -- it still sounds pretty convincing.— erin
- I grew up in Hawaii, and was pretty sure that our country, the United States, was the fiftieth stateAnon