I was very insistent that Grand Prix was pronounced Grand PRICKS
I would argue with my parents all the time that it couldn't possible be pronounced the way they said it was.
A childhood belief about sport

others believed things like this
- I was convinced that Indians had dug the Grand Canyon.— Tom Sackett
- when was little i used to believe that if you won the grand national you would become prime ministerAnon
- When I saw my grand mother was very old I used to believe an Egyptian mummy!!!!
— Eomer83 - My Grand father told me that if i swallowed chewing gum i would stick to the toilet— Mr Jones
- i used to believe that 'island' was pronounced 'is-land' instead. I know im not alone on that one! :)
— Da KornMeal - I used to think that New York was pronounced "Yew Nork"Anon