We know from experience that controlling our anger and antagonism is difficult, not least so because our naked-primate, first-responder instincts are fierce and hard-wired into our brains. But it is also difficult because many of us who are habitually resentful, vindictive or cruel do not want to get over our anger. The harsh response is warranted, we believe, because (fill in your justification).
Given your justification, it follows that being tense, mean-minded, aggrieved, bitter and punitive is worth it, doesn’t it? Not really. Spending so much time mentally entertaining or sharing your angry, resentful and vindictive thoughts is self-tormenting and a misuse of your attention and energies.