When I was little I used to believe that the reason old ladies had blue or purple hair was because it grew that way. I don't think my mum has ever laughed as hard as the day I adamantly told her Aunty Alice's hair grew purple and she revealed it was because it was dyed.
A childhood belief about hair

others believed things like this
- I used to think that everybody's hair was black and if you had blond hair, you dyed your hair.— ~_~CoolKid93_~_
- I used to believe that after I cut my stuffed animals hair that it really grew back! — Kristy
- I use to believe that your hair grew because you wash i.e like watering a plant — HJON
- When I was younger I cut my Barbie doll's hair and wondered why it never grew back.Anon
- I used to believe that people's brains differed in colours. I always wanted purple brains for some reason.— Katrina
- When I was little, my dad told me that if you pee in the pool the water will turn purpleAnon