I once saw a commercial or something that showed a kid who'd left the faucet running while he was brushing his teeth. the water came from a pond right outside his window, where there was a happy little fish swimming around, but the fish drowned because the kid had left the faucet running and sucked the pond dry. after i saw that i never used faucet water to brush my teeth, because i thought that it was pond water.
A childhood belief about bathrooms

others believed things like this
- I used to believe that eating burnt toast would make your teeth whiter and would brush your teeth for you.— Natasha
- I used to believe that if I didn't brush my teeth at night, ants would crawl into my mouth and eat my teeth.Anon
- I thought that hydrogen was pure water (since I knew hydro- meant water) and H2O was impure some how— Hexetic
- I thought "Angel of the Moring", by Juice Newton said "just brush me teeth before you leave me"!!!Anon
- I used to believe that if i splashed water on the wall during a bath, the water would turn into spiders— justin
- that bathroom tap water was recycled "potty" water from the toliet. — livingdeadgirl