I thought "Money for Nothing" by Dire Straits was a fictional advertisement for a store like Best Buy, and that they were trying to get you to buy something more expensive than just a CD with music on it by insulting the artist.
A childhood belief about misheard lyrics

others believed things like this
- I thought Bonnie and Clyde were fictional characters.Anon
- I thought braces were made out of precious metals and that's why they were so expensive!— Sp' Iyulgar
- when i was little, i thought that a con artist was a person that painted pictures of people commiting crimes— kimkim
- I used to believe that albatrosses were a fictional species created for the Disney movie "The Rescuers"Anon
- I used to think a con artist was someone who painted pictures in prison.— Brandon Campbell
- I used to think that a con artist was someone who was really good at making complicated art.Anon