I will admit, this is always a struggle for me. It is hard for me to offer forgiveness. I would say I need to forgive my parents for childhood issues I have.
There are other things in the world I choose not to forgive. I will mention that I was watching an interview with Dr. William Petit (the man whose whole family was murdered while he was unconscious) and he had me rethinking the idea that you are "supposed" to forgive. Dr. Petit said, “You can forgive somebody who stole your car. You can forgive somebody who slapped you in the face. You can forgive somebody who insulted you. You can forgive somebody who caused an accident. I think forgiving the essence of evil is not appropriate.”