Everybody knows that if they're happy then usually the people around them are happy, or that people around them happy make them a little happier; that's a proved thing, like "I give to you and you give to me"; they all know that but they haven't thought about it to the point of every action that they do. That's what it is with every action that you do, there's a reaction to it, and if you want a good reaction then you do a good action, and if you want a bad one, then you punch somebody.