Flow is great, but it's a very different concept from happiness at work. Flow refers to one specific mental state, and different people want different amounts of flow in their lives. But it's completely possible to be passionate about what you do and love your life without ever experiencing flow.
I agree that oversimplifying can make things worse. There are really dangerous simplifications out there, such as "just follow your passion!" or "do what you love and the money will follow." But Self-Determination Theory[1] is a well-developed field backed by research and experimentation-not something pulled out of thin air like most happiness advice.
I agree that oversimplifying can make things worse. There are really dangerous simplifications out there, such as "just follow your passion!" or "do what you love and the money will follow." But Self-Determination Theory[1] is a well-developed field backed by research and experimentation-not something pulled out of thin air like most happiness advice.
[1]: http://en.wikipedia.org/wiki/Self-determination_theory