What’s the silliest thing you believed as a child that you still find funny?

Invisible man in the sky, invisible man below the earth and that people talk to them.

(Not knocking it if you believe in it. That's all you, but don't try to force your belief on me)

I used to believe that belly buttons were used to feed babies before birth

I also believed that actors had to re-record their performances for every rerun of a show. I didn't know they filmed them.