Forgiving people is a challenge.
It is tempting, especially in an argument, to bring up what one has done in the past. But, to truly forgive, you must lay to rest what is not relative today.
Retaining anger, resentment, or bitterness stunts your growth by blurring you to the realities around you and ultimately causing others to suffer behind the emotions you are harboring.
Extract the lesson from the event and understand that it is no longer destiny but history.
Forgiveness is more powerful than anger and will allow you to grow in a place that cannot be measured.