I'm a nice person, probably too nice in the past. Now I am extremely introverted, even though work and such forces me to pretend otherwise.
My past has made me who I am. People tell me to forget it, but what we see, experience, and live through influences our beliefs, our personalities, our reactions, etc.
I spent many years wondering why others could not treat me decently. Now, I just treat myself decently and accept that I just don't fit in. I am carving my own niche in the world.