I used to think that when people were talking about World War I and World War II that they were saying "war war one" and "war war two". It wasn't until I was in elementary school when I read it in a history book that I finally figured it out.
A childhood belief about wars

others believed things like this
- I used to think a world record was a record of all the people in the world singing .— JACK REGAN . [SWEENEY . ]
- I thought the world was black and white because of all the smoke from the bombs in Second World War.— Bjoern
- I used to believe my dad was the best male figure in the world and wondered why he wasn't president already.— Ivy :)
- Until a few years ago, I believed this was a "doggy dog" world, rather than a "dog-eat-dog" world.— jemima
- I used to think that the phrase "It's a dog eat dog world'' was its a dogey dog world.— Gabral
- When I was in elementary school I use to think that teacher lived at school at their desks all year long.Anon