Why did God create the world and fill it with such erratic, unpredictable creatures as we human being are? One Jewish tradition would have it that God made the world the way it is so that we would have the possibility of being nice to each other. The Talmud teaches that when a person does a good deed when he or she didn't have to, God looks down and smiles and says, "For this moment alone, it was worth creating the world."
When we go out of our way to be kind to someone, in large ways or small, our reward is the knowledge that we have redeemed the world.
— Harold S. Kushner, Practice Random Acts of Kindness by Editors of Random Acts of Kindness