Isn't it nice when we're heading into a store or restaurant, and the person in front of us holds the door open for us? It's a small moment of kindness, of friendliness, among strangers. It makes us smile, say, "Thanks," and then what do we do next? We turn around and do the same for the person behind us. We pass the kindness along. It not only makes that person feel good, but we get an extra shot of a feeling of goodwill. And who doesn't need that?