Being unable to forgive compels you to discontent and internal war. Holding old grudges, being bitter and fueling constant anger create an inner turmoil that chains you to reliving past hurts. Do you really enjoy lugging that ball and chain around? Worst still, your health is impacted by long-lived grievances and your blood pressure, heart rate, physical and spiritual health will be suffering.

• It is hard to live a calm life when you constantly hate, feel a need to avenge and see ghosts in every shadow. Forgiveness allows room for kindness and self liberation. Forgiveness nurtures a sense of calm because you no longer spend a big part of your life resenting other people.
• Remind yourself that when you forgive, you remove the toxic feelings from your life; it is not about condoning what another person did but it is about no longer letting that person’s actions run your outlook on life.
• When you feel yourself getting angry at someone that hurt you, try to stop and think. Breathe slowly for a second. Does being angry make your life better? Does the hate you feel make you happy? Would the people that really love you want you to keep suffering like this? The answer to all of these questions is “no”…so release those negative feelings and seek out positive ones instead.

Source: wikiHow