Mihály Csíkszentmihályi: As many a thinker since Aristotle has said, everything we do is ultimately aimed at experiencing happiness. We don't really want wealth, or health, or fame as such—we want these things because we hope they will make us happy. But happiness we seek not because it will get us something else, but for its own sake.
Sonja Lyubomirsky: I use the term "happiness" to refer to the experience of joy, contentment, or positive well-being, combined with a sense that one's life is good, meaningful, and worthwhile. However, most of us don't need a definition of happiness because we instinctively know whether we are happy or not.
Ed Diener: The word "happiness" means many things. It means positive emotions. It means life satisfaction. It means generally your life is going well. It means many different things in the different ways people use it. Everyone has this general idea. So I don't define happiness. I try to use these other, more exact terms, such as positive emotions, life satisfaction, marital satisfaction.