Mirrors

Isn't it amazing that we have an innate fear of mirrors.
Why does something like a reflection scare us?

Most people begin feeling uneasy after staring at themselves for long periods of time.
Why do we not trust our own appearance?
As if we look at ourself and believe this person I am looking at is not me
Rather
This one is malicious
This one wants to hurt me.

when Someone has seen themself blink.
That 'I caught you' moment.

Fear is inherited at birth.
Passed down by ancestors to protect us.
In the past, those who didn't fear the bit of a spider would pick it up would die by its poisionous fangs.
While those who avoided the spider would live on and pass down this knowlegde in the form of fear.

Which begs the question:
What about a mirror is so dangerous, that has been I have been inherited to fear?

I know I shouldn't threaten my reflection.
And
I wouldn't just stare at myself?