Contrary to what we usually believe.. the best moments in our lives are not the passive, receptive, relaxing times — although such experiences can also be enjoyable — the best moments usually occur when a person’s body or mind is stretched to its limits in a voluntary effort to accomplish something difficult and worthwhile. Struggling to overcome challenges, and then overcoming them, are what people find to be the most enjoyable times in their lives. People typically feel strong, alert, in effortless control, unselfconscious, and at the peak of their abilities. Find rewards in the events of each moment . . . to enjoy and find meaning in the ongoing stream of experience, in the process of living itself.
Mihaly Csikszentmihalyi, Flow: The Psychology of Optimal Experience