The first thing to realize about the terrible Chain of Resentment is that you don’t have to feel it. The experience of resentment is a choice you make.
The second thing to realize is that the Chain of Resentment binds the self more than anyone else. Breaking the chain of resentment means unburdening the self, setting the self free.
No one can just “let go” of resentment. You can resolve resentment only by investing more value in your life. The more you value, the less you will resent. The more compassionate you are, the less you are able to resent.
— Steven Stosny, Manual of the Core Value Workshop, p. 74.