My gran always told me to 'go easy on the tomato ketchup, because I'm not buying any more', this made me think she was going to die when the bottle was empty, and subsequently made me feel very guilty whenever I put it on my food - in very small amounts.
I realise now she was fibbing, since she lived 'till I was 40!
A childhood belief about general

others believed things like this
- my gran tod me that rabbits made a noise that went "map map"— Lise
- i used to think a small man named homer lived in my grandmother's freezer and made ice. — ana
- i thought salt made food cold, since pepper made it *hot* — cattiva
- I used to think that a tornado was a tomato and lots of tomato juice would got flying around.— sam
- I believed that the inside of a tomato was a small, living creature and I flatly refused to eat that bit.Anon
- I used to think eyedust was made by people who lived in your eyes and made buns.— The world looks to me.