I've never let my mum live down the time when she was singing 'Take That Look Off Your Face' from the musical 'Song and Dance' (Andrew Lloyd Webber/Don Black).....she sang 'There's more than one car with knickers on'!
Personally I'm yet to see one car like this!
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
- When Madonna sang "let the choir sing" in "Like a Prayer", I thought she was singing "love by proxy"— Kristen
- for my little sis -
Paul McCarty song "Band on the Run" but when she sang it it was "Man has the Runs"Anon - I used to think that the actors on tv shows sang the show's theme song.Anon
- i thought I got one year older when my family sang the birthday song.— I am the ghost
- Until I was about 15, I beleived my Father was the person who sang the "Cheers" TV Show Theme Song.— Dustin