I think it is interesting that you brought up a mirror, because I was just thinking about reflection. I think the reason so many of us don't like ourselves is that we have very rarely had the good in us reflected back at us.

If you look outside yourself and all you see is bad coming back, then, as social creatures, we begin to incorporate that image of us. When someone begins to reflect back the good that is in us, it's like "wow!".

It's hard to accept or understand because that positive reflection begins to change the way we see ourselves, and have seen ourselves for years.

It would be nice if we could innately develop an inner sense of goodness, but I think in the absence of external reinforcement, it's too easy for that sense to wither and die.