Movies like this are the reason I see over a hundred of them a year. An interesting story, very real characters and it never drags. Joan Allen plays a woman who never quite recovers after her husband leaves. Her bitterness is like a cancer that affects everyone around her. After an event puts it all in perspective, you can take a breath and believe that the characters survived and learned from the experience.
Most amazingly, Kevin Costner provides a new persona. He’s usually in love him ("Tin Cup," "Field of Dreams," "Dances with Wolves") or hate him ("Waterworld," "The Postman") mode, but in "The Upside of Anger," he gives us a new type: good actor.
[2009: I watched it again in October, 2008, and was just as impressed.]