Guy Winch is a licensed psychologist, author, and speaker. He is the author of Emotional First Aid: Healing Rejection, Guilt, Failure, and Other Everyday Hurts and other books. In this TED Talk he makes a compelling case for emotional hygiene -- taking care of our emotions, our minds, with the same diligence we take care of our bodies.
My late mother-in-law used to swear by "Irish* Alzheimers" where you forget everything but the grudge. It doesn't have to be that way.
* Insert whatever nationality or ethnicity in your family.