“The ultimate test for the ability to control the quality of experience is what a person does in solitude, with no external demands to give structure to attention. To fill free time with activities that require concentration, that increase skills, that lead to a development of the self, is not the same as killing time by watching television or taking recreational drugs.”
Mihaly Csikszentmihalyi, From his book The Psychology of Optimal Experience

Mihaly Csikszentmihalyi: born in 1934, is a psychology professor at Claremont Graduate University in Claremont, California and is the former head of the department of psychology at the University of Chicago and of the the department of sociology and anthropology at Lake Forest College. He is noted for his work in the study of happiness, creativity, subjective well-being, and fun, but is best known as the architect of the notion of flow and for his years of research and writing on the topic. He is the author of many books and over 120 articles or book chapters. Martin Seligman, former president of the American Psychological Association, described Csikszentmihalyi as the world’s leading researcher on positive psychology.[1] He is one of the most widely cited psychologists today, in a variety of fields related to psychology and business.