Forgiveness doesn't excuse their behavior. Forgiveness prevents their behavior from destroying your heart. Deciding not to forgive hurts not only the other person but you as well. Not learning to forgive hardens the heart and makes shallow the soul.
Squirrel: I'm sorry to bother you but the bird feeder is empty. (A squirrel, my mother named Petey, once got on the porch railing and rang the doorbell because he wanted some peanuts!) Now I call all squirrels, "Petey"