I believed that the word "contents" was a verb and meant "explodes". Why? Cans around my parents' home all had printed upon them the same thing: "Warning: contents under pressure". I figured that if you squeezed the can, it would explode. I handled all cans very carefully for a very, very long time!
A childhood belief about around the house

others believed things like this
- For years and years I believed that tuna must be really little fish because they came in such small cans!!— Gisela
- I used to believe there were calves' heads in those cans of Pet Milk.— Ron
- I used to believe that Internet banking printed money out of the printer in our home like an ATM. Anon
- I always believed as a child your stomach was a big hand which squeezed your food out through your bum....— amc
- I used to believe that ATMs actually printed out the money fresh every time. — Kitty B
- my husband believed, until recently, that the word "several" meant seven of something. — sheryl