I thought for ages on the song 20th Century Boy by Marc Bolan & T-Rex, the verse was "wine tastes fine, wine tastes good, something, something, just like Robin Hood!" when the REAl ones are "friends say it's fine, friends say it's good, everybody says it's just like rock'n'roll!". I still have no idea where the Robin Hood bit came from lol
A childhood belief about misheard lyrics

others believed things like this
- I used to think "Robin Hood and his merry men" was "Robin Hood and his *married* men."Anon
- When I used to see a sign saying "Littering Fine" I thought they meant if you littered REAL GOOD!— Lou V.
- My dad thought robin feet were made out of wood because they look like twigs.— Molly
- Picking your nose and eating it. Hey! Tastes like chicken and only half the calories— Henry the Seventh
- I always thought there was a drinking age for coffee, because it was an adult drink like beer and wine.Anon
- I thought that the song "Built this City" by starship went as follows. "Milk and Cereal, Rock and Roll"Anon