Scott Adams, the Dilbert cartoonist, offers 3 key happiness factors in his book, How to Fail at Almost Everything and Still Win Big - Kind of the Story of My Life. #1 Schedule Flexibility - do what you want, when you want. This allows for naps, which leads to point # 2: Feeling Healthy (also, diet & exercise). Lastly, Expecting the Future to be Good. See Chapter 30 in his book for full explanations.