I can't reply to everyone but this is basically the message.
You should not hold on to bitterness and carry that baggage into the present and future. Let it go! It is ok to feel emotions, but don't hang on to them, and do not stuff it down inside.
You have to acknowledge the pain and release it through healthy outlets. Meditation, talking/venting/crying, sports/working out/yoga, journaling, running/taking a walk, drawing, creating.
Do not ignore it! It will come out one way or another. You want it to come out in a healthy way, not through stress, high blood pressure, drinking, drug abuse, violence, depression, anxiety.
Take negative experiences as a learning experience and grow from it. No pain, no gain. No struggle, no strength.
We need to be understanding and not dismissive. No man is an island. We are all connected. Hurt people, hurt people. So heal yourself so you won't spread negativity. Remain healthy and positive. Protect yourself against negative people. Do not take it personally, realize that they are hurt and projecting their pain.
The only person you can control is yourself. You can't control how people act, but you can control, how you react.