When I was a kid, I thought that the line in the song, "You're the One That I Want," from Grease went as follows:
"You're the one that I want, John Travolta, woo, hoo, hoo..."
A childhood belief about misheard lyrics

others believed things like this
- I used to belive that John Travolta's name is Johntra Volta— Maria
- As a child, I thought that Olivia Newton-John was Elton John's wife and Juice Newton's sister.— Connie
- As a child I used to think that Olivia Newton-John and Elton John were married.
Boy, I was way off.— Lisa - I thought that Olivia Newton John was a group, Olivia Newt and John. — Sam O.
- I used to think that Olivia-Newton John was three people like Sharon, Lois and Bram....Olivia, Newt and John— J
- I always thought that "elbow grease" was a type of lubricant until about 2 years ago. I'm 19.— Erika