Compassion literally means to feel with, to suffer with. Everyone is capable of compassion, and yet everyone tends to avoid it because it's uncomfortable. And the avoidance produces psychic numbing -- resistance to experiencing our pain for the world and other beings.
What keeps us from forgiving the people who hurt us is that we have not yet healed the wounds they inflicted. Forgiveness is the gift at the end of the healing process. We find it waiting for us when we reach a point where we stop expecting "them" to pay for what they did or make it up to us in some way. Yet, forgiveness is moving on. It is recognizing that we have better things to do with our life and then doing them.