Mirrors are the world's worst enemy.
They strip away the outside and show us all our hidden secrets; each insecurity, each flaw, each red-spotted blemish, each patch of skin that somehow seems darker than the others.
Mirrors consume us; the gobble up our exterior and spit out the raw, ugly inside: you're ugly. you're not good enough. you'll never look as good as her. We may be perfect in our heads, but when it's time to look in the mirror, we can see how much weight we've gained, how horrible our nose shapes are, how chubby our cheeks are. The mirror will always be lurking, waiting to taunt us and mock all the hard work we've done to prove it wrong.
But the mirror only gets into our heads if we let it.