Mihaly Csikszentmihalyi

Grew up in wartime Europe, watched adults who had lost everything and noticed that a few of them kept something the rest did not, and spent a career trying to identify what.

Flow names the state: complete absorption in a task that stretches ability just past comfort, where self-consciousness disappears and time distorts. He found it in surgeons, rock climbers, factory workers and chess players alike, using a method that paged subjects at random and asked what they were doing and how they felt.

The finding that unsettles people is that the flow state showed up far more often at work than during leisure, and that most people report being happier working than relaxing while believing the opposite.