For some unknown reason, my (normally kind and loving) Granny told me that if I looked in the mirror too much I'd see the Devil standing behind me. Consequently I was absolutely terrified of looking into mirrors in empty rooms, or of even passing by mirrors at night, just in case. To this day I have a residual uneasiness about looking in a mirror at night.
A childhood belief about mirrors

others believed things like this
- I believed that if I looked too long in the mirror admiring myself the Devil would appear.— Paul Elletson
- I'm scared of mirrors because I think that there are ghosts in mirrors— est
- If you stare into a mirror in almost complete darkness, the devil will appear instead of your reflection.Anon
- when i was young i used to believe that my image on a mirror would come to life if i broke the mirror.Anon
- one of my friend's was told by his father that if you didn't turn mirrors over the reflection would run out.— pri
- I used to believe that there was a person in the mirror who looked exactly like meAnon