Human happiness depends on the wide range of factors. Some of them are common to all individuals while the others are specific. All people feel happy if their loved ones recover from a tough disease, but not all of them have the same feeling if, for example, the president prohibits drilling on the ocean coast. People do not share all the values they have that is why one and the same action affects all of them differently. As we can see, happiness depends on external factors or actions of other people. But there is another type of happiness that depends on the doer of the action.
No matter whether we realize it or not, good deeds make us feel better. It usually happens when we give some gifts to people we appreciate or act fulfilling our own moral standards. The psychology behind this process is simple: the ability to act the way we consider to be right assures that we have control over our own life. Clear conscience make us live in harmony with our own self, which does not happen so often in the reality. Some people are forced to act against their principles in order to benefit from their failure. Such actions have a strong self-destructive power particularly because they contradict universal moral principles of the individual.
Acting morally is necessary for well-being indeed, but we shall not forget that other people may have different moral values. We all have a sense of justice and satisfaction whenever we do what is morally right for us.