"Resentment is the "number one" offender. It destroys more [addicts] than anything else. From it stem all forms of spiritual disease, for we have been not only mentally and physically ill, we have been spiritually sick. When the spiritual malady is overcome, we straighten out mentally and physically. In dealing with resentments, we set them on paper. We listed people, institutions or principles with whom we were angry. We asked ourselves why we were angry. In most cases it was found that our self-esteem, our pocketbooks, our ambitions, our personal relationships (including sex) were hurt or threatened. So we were sore. We were "burned up."
Taken from the Big Book of AA, Chapter 5 How It Works, page 64.