Erasing your memory of past hurts and injuries and releasing yourself from the bondage of anger and resentment are quite necessary, if you want to be peaceful and happy here and now. There is a magical transformation of your mind and heart when you sincerely and truly forgive.
Negative emotions such as grudge and hatred do not diminish when you indulge in them. Such indulgence makes you more miserable. You may even enjoy such misery as it builds up your ego with its sense of separation and being very special.
As the misery intensifies, it may lead to a sense of desperation and suicidal depression. Yet you can come out of deep misery at any moment when you decide to forgive yourself and others fully. Then you are able to accept yourself and others exactly as you are here and now. That means peace and love. That is the magic of forgiveness. Then you realize that you are essentially peace, love and joy. That is the glorious truth of your being. Being true to yourself is genuine freedom.