To me, football (or actually, futbol) has always meant what is called soccer in the United States. When I first saw American Football at a fairly young age, I thought that players in that sport had gigantic muscles, though it turned out to be their shoulder pads.
A childhood belief about sport

others believed things like this
- When I was little, I used to believe that football players really had shoulders that big.— Angie
- I used to believe that America was one of the states of the United States.— Limor
- I'm an American, and for a good long while I thought that Boxing Day involved the sport of boxing.— miss Taken
- I used to believe that a football ref's flag was a banana peel.Anon
- When I was a kid, I used to think that the only way you could play football was if you had giant shoulders.— Sam
- I used to think that the Hunchback of Notre Dame was a football player.— Wendy