Anger and Bitterness

Here's a terrific paragraph from the book on anger that I'm reading at the moment. It also mentions bitterness; unfortunately, this seems to be a recurring theme in this blog and one which I raise again with some hope that I'll soon be able to put past hurts behind me:

"Anger is an automatic, natural, God-given response in our bodies to the presence of danger. Whenever real or potential danger is present, or we perceive danger as present, the 'anger button' goes off, signalling this danger. Anger is a natural, physiological response to danger that God has built into all of us. If anger is used improperly, or ignored and repressed, it turns into bitterness. Bitterness, then, is a choice we make to hold the power of anger as a means of revenge. In our minds we argue, 'Because you hurt me, I am going to hurt you in return.' Bitterness is both unfulfilled revenge and unfulfilled anger."
(from 'Healing Life's Hurts' by Graham Bretherick)