For years I heard the expression "black as the ace of spades" as "black as the ace of SPACE!" I finally learnt the truth when we were sat down at dinner and I challenged my Dad with "how do you know, have you ever been there?" when he said the aforementioned expression!
A childhood belief about speaking

others believed things like this
- I used to think that the expression "The former or the latter?" was actually "The farmer or the ladder?" — Fitzwilliam
- I forgot the expression "not cricket", so I said, "not tennis" instead.Anon
- My friend told me she had invented the expression 'Gordon Bennett' and I believed her!— SueE
- I thought the expression "so funny I forgot to laugh" was literal instead of sarcastic— Not so funny after all
- I thought black people were black because they drank chocolate milk. — Shelby
- When i was a child, i used to believe that when people ate black beans, they became black— Mar'ia Elena