To forgive or not to forgive?

I believe forgiveness varies greatly between people. As suggested by the video, As We Forgive, some people almost can't bring themselves to forgive. Rosaria forgave Santeri almost immediately. Chantal, on the other hand, was still irate over the murder of her father by one of his best friends. She took over six months to forgive him. If I had been put in that situation, I don't know that I could forgive someone for murdering my family. Sometimes, I can easily forgive someone for doing something that angered me. A good night's sleep helps calm me, and I'm completely cooled down the next day. But I do hold grudges, and a problem that huge would stay with me forever. I am naturally a very stubborn person, and grudges come easily to me.
I think forgiveness and reconciliation are possible. One just has to open his heart to change and accept the past for what it was. Many people are unwilling to forgive because of the suffering they have endured and the memories created during that suffering. Forgiving is setting yourself free of a burden you have shouldered for a long time. As someone once said, "To forgive is to set a prisoner free and discover the prisoner was you."