I used to believe that the little plastic size tags you got on hangers in clothes shops were chewing gum!
A childhood belief about chewing gum

others believed things like this
- that....I do not grow old (in size)...rather my clothes and shoes shrink..— mayank
- I used to think small furniture shops were basically cottage converted charity shops.Anon
- I used to think that the tags on cows ears were actually earings.— Kelly
- I used to think that doctors added plastic to your face in plastic surgery.— caro
- I used to think that plastic surgery actually involved using plastic.
— JohnJ - I used to believe that plastic surgery was done with plastic knives.— Vicki J.