Well it seems a little oxymoronish to Kill and be Kind at the same time.but being kind is the right thing to do, maybe instead of killing them they will learn to be kind also, or just be kind in return. The Golden Rule if you will.
Let it go! when you get really angry and you want to insult people. breathe in then let it go let go of all that is not God / Good / - let go of anything that weighs you down - let go of hurt - forgive yourself and forgive them