I thought, for a very long time, that in the song (I think it is by Joni Mitchell...) in which the line is 'Pave paradise, put up a parking lot' the line was really 'Gay pair of guys, put up a fucking lie'. I was corrected by a friend when we heard it in a large store and I commented on how I wouldn't have thought they could play a song with the f word in a mall.
A childhood belief about misheard lyrics

others believed things like this
- i thought the line "saving my face" from the KT Tunstall song of the same name was "shaving my face"Anon
- I used to think that the song"Stayin Alive" said "Staying In Line" like at school when I was little. — MacKenzie
- I thought the line in the song "more than a woman" was "four-legged woman".— boo
- I used to think that the line in the song "Life in the Fast Lane" was "Fights in the Bat Plane".Anon
- When I first heard Bruce Springsteen's song, "Born in the USA," I thought that the song was "Porn in the USA"Anon
- I thought a highwayman was just someone who helps pave the road and stuff like that— Nate