Subjective well-being refers to people's evaluations of their lives in both thoughts and feelings, and includes states such as life satisfaction, positive feelings, and happiness. Deciding which of my laboratory's findings on subjective well-being are the most important is a tough decision. In 1984, I authored an influential review of the field. At that time there were a few important studies of subjective well-being, but not many of them, and very much was unknown. In 1981, the year I entered the field, there were fewer than 100 studies per year on happiness; in 2014, there were 14,000! I have conducted research on most areas in this field. Thus, nominating one important finding is difficult with such an array of choices.

The findings I've chosen as my most important are those showing the many benefits to later behavior of high subjective well-being. My research and reviews of the literature indicate that those who are high in subjective well-being on average exhibit superior health and longevity, social relationships, work performance, and citizenship. It is not that these factors simply cause high subjective well-being, but that subjective well-being is likely to increase them! There seems to be a virtuous circle between positive feelings and desirable behavior, in which each reinforces the other. Think of the implications of these findings: Happy people not only enjoy life more, they also tend to be healthier and have more friends, and they are better citizens who are successful at work as well.

Thinkers have expressed very different opinions about the value of happiness. On the one hand, philosophers such as the Utilitarians have held happiness to be the true goal of life, the one outcome that makes all life worth living. In contrast, other thinkers describe happy people as shallow and narcissistic, not able to see problems and improve the world. A third view sees happiness as desirable as long as it results from virtue and fulfilling needs, such as for meaning and purpose in life. My view, now supported by substantial research, is that happiness is itself a virtue. This new approach argues that although happiness is pleasurable, it is much more than hedonism because it so often helps people function more effectively and less selfishly.