What is the nature of (un)forgiveness?

A (hopefully accurate) paraphrase of what Lindey A. offered:

Unforgiveness is essentially discontent. Discontent leads to jealousy, especially of others who are content. We personally cope with our own discontentment and jealously by becoming indifferent to those 'others'. Indifference leads to disconnection with those 'others', which often leads us to hate those 'others'.