In our studies, we found that every flow activity, whether it involved competition, chance, or any other dimension of experience, had this in common: It provided a sense of discovery, a creative feeling of transporting the person into a new reality. It pushed the person to higher levels of performance, and led to previously undreamed-of states of consciousness. In short, it transformed the self by making it more complex. In this growth of the self lies the key to flow activities.
Source: Csikszentmihalyi, M., 1990. Flow : the psychology of optimal experience, 1st ed. ed. Harper & Row, New York. Photo: Fluid Painting 79 Acrylic On Canvas (Mark Chadwick/Flickr).