We all feel resentment toward certain people. The neighbor who called you "pork chop" as a child. Mr. O'Neil, your third grade teacher, for that undeserved D in biology. Doug, the obnoxious new guy at the office, for stealing your big account. The list goes on and on.

Long after the objects of our grudges disappear from our lives, those feelings remain in the subconscious. They rear up when something reminds us—be it one of those "the other white meat" commercials, the very mention of a science fair, or anyone who even closely resembles Doug. "People who are unable to share angry feelings in the moment will form a resentment," says Shannae Rickards, Ph.D., a psychologist in private practice in Thousand Oaks, California. "This retained anger will lead to avoidance of the people who caused the anger."

In addition, stifling your emotions leads to headaches, stomach pains, interrupted sleep, and addictions, says Rickards. "This stress will settle in the body in different ways," she adds, "none of them good." Fortunately, there are ways to keep anger from turning into a festering grudge.

The best option is the straightforward approach: Tell the guilty party that you're getting mad. "You'll be healthier and feel better after you do it, and there won't be any misunderstanding between the two of you," says Rickards.

If it is an unreasonable in-law or boss who keeps pushing your anger button and you don't feel you can confront them directly, talk about the problem with someone else. "Sharing with another person won't take a grudge away, but it will help ease it," says Rickards. This option is also helpful when the person you hold resentment against is no longer alive or is completely out of your life. "If it is not possible for you to talk to the person directly," advises Rickards, "write a letter to them to get your feelings out."

In therapy, Rickards asks clients who feel resentments to write down a grudge inventory: what happened, who was involved, what effect it had on self-esteem. "Rather than sitting there and blaming the world for what has happened, I try to encourage my patients out of the victim stance," says Rickards. "The goal is to empower people and let them know that they play a part in which people and circumstances are in their lives. When you're aware of what's bothering you, you can start to cope with it and avoid similar problems in the future."