i used to believe that z's came out of your mouth when you slept. so for many years i pretended to be asleep and open one of my eyes the tiniest bit to catch those cheeky z's escaping.
A childhood belief about sleeping

others believed things like this
- I used to believe that if I slept with my mouth open that spiders would crawl in there and live in my stomachAnon
- When I was little my friend told me that if you snease with your eyes open you eyes will fall out!Anon
- my brother told me that if i ride my bike with my mouth open i will swallow my tounge. Anon
- I used to believe that if you sneezed with your eyes open you would die!— Becky
- I used to think wall outlets looked like little faces (eyes and mouth), and so I would talk to them sometimes!— EJ
- I used to believe that newborn babies didnt open their eyes for a few weeks like kittens :) — Cash