I was terrified of looking into a mirror when in the bathroom unattended. My grandmother had warned: "if you look in the mirror too long, you'll see the Devil in it!"
Not until I had outgrown the fear did I realize it was a metaphorical admonition against narcissism.
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
- 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
- I had a fear of seeing a person in the corner of the mirror(most of the time a morlock)— Shane
- Grandmother told me if I whistled in the bathroom the devil would come get me because I was whistling for him.— Peanut @ Lake Tawakoni Tx
- I used to think that if a mirror with me in it breaks, I break.Anon