When I was six, I thought that if you got a pair of a type you already got in "Go Fish", it didn't count. For example, if you'd already gotten a pair of jacks, the second one didn't count. And I thought that if you got a pair of a type you already had, the solution was to discard one of the cards that formed the pair and not use it.
A childhood belief about hobbies

others believed things like this
- ... i used to believe the more stripes my pair of sneakers had, the faster i would run ...— wilbur
- I thought that Count Dracula was the count from Sesame StreetAnon
- I thought that “selfish” was a type of fish— Enrico
- I thought to count to one thousand you did 1-100, then 100-199, then came 1,000.— Anon!
- When I was little i thought that seconds were so fast that you couldn't count them.— Baby
- I used to believe that it would take forever to count to 100— Jeff