I used to belive that the GB plates on the back of Britsh Coaches mean't the driver was Getting Better, not its proper meaning of Great Britain. I saw it on the back of an old white van years later and told my dad, who then told the van driver. Needless to say, the driver of the white van didn't take too kindly to this comment.
A childhood belief about buses

others believed things like this
- I used to believe that a "ghost-driver" was a car driving with a white sheet over it.— Nynke
- I always used to think that Ozzy Osbourne was a racing driver!
Anon - I wanted to grow up and be a truck. Not a truck driver, a truck. Anon
- I used to believe that my school teachers lived inside the school and my school bus driver lived on the bus. Anon
- back in the days i thought the world was black and white like in the pictures— compaq
- I used to think that the word Great was added to Britain because they won the Second World War.— Age