Apparently when I was younger I didn't cotton on for quite a long time that the mirror reflected things, so I used to think that there was someone else in the mirror whenever I looked in it. No matter how often people would tell me it was me, I wouldn't believe them. Interestingly, although I am now in my 20s I often look at my reflection and it doesn't seem like me.
A childhood belief about mirrors

others believed things like this
- I used to believe that when you cracked a mirror your reflection would come and take over your body!— XxXAbbeyXxX
- I believed that if I looked too long in the mirror admiring myself the Devil would appear.— Paul Elletson
- I used to believe that my reflection in the mirror was my evil twin that always had bad hair. XDAnon
- 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 used to believe that there was a person in the mirror who looked exactly like meAnon