In my professional life one of the things I am really passionate is Soccer. And be able to pass my knowledge to a kid or college athlete gives me more energy to do better. I believe that when people goes to work just for a paycheck are totally out of that area of strength. once I read that "the day you start doing what you love ... is the day you stop working". If you do what you love for a living you will be a that sweet spot that Marcus Buckingham is talking about.