What is the symbolism of Cole's dance of anger?

Cole's dance of anger is a symbol of his readiness to let go of the intense anger he's felt for most of his life. As part of the dance, he screams out before saying, “I'm sorry.” The final step in his dance is that he says “I forgive you.” The author doesn't spell out who Cole is forgiving but it seems obvious that it refers to everyone who has led Cole down his path toward destruction, including his parents. Cole is also referring to himself and realizes that it's time for him to forgive himself.