When I was little, my brother once told me that if you didn't shut the lid to the toilet when you flushed it, and if there wasn't a ceiling, then some of the water would go all the way to outer space. I imagined that a small amount of water (not enough to see) would be shot into the air when you flushed it, and it would then float up and up and up. I basically figured it just evaporated, which it does so I guess I wasn't that gullible...
A childhood belief about bathrooms

others believed things like this
- I used to believe that if I flushed the toilet before I showered, I would take a shower in dirty toilet water.— Chris D
- I used to beleive that if you flushed the toilet that it would explode and all the water would shoot out.— Michelle
- I used to believe that Limabeans would kill you if you didn't eat them.
I flushed them down the toilet.— Lima - I used to believe that monsters lived in my toilet and they ate my poop and urine when i flushed the toilet.Anon
- I used to think if I left the toilet seat open my cat would get flushed down the toilet.— G
- I used to believe that the toilet would suck me down if I flushed it.— :-)