Flow -the magic drug

The author (with the hardest name ever, -never learned to spell it right) Mihaly Csikszentmitalyi who wrote the classic book FLOW, also did a TED-talk about Flow and Happiness. You and it on:

https://www.ted.com/talks/mihaly_csikszentmihalyi_on_flow

And I can really recommend the book as well, for those who haven´t red it. It contains interesting facts and findings from decades of research about flow and how it works.