Physics, Metaphysics and Happiness

Happiness is unusual because everyone has different views of how to achieve it; or once acquiring it, what exactly happens? I have to disagree with the traditional physics view that happiness is the final end of all activity because the most successful people I know are also the happiest and hardest working. Just because they are successful and happy, doesn't stop them from working even harder to achieve there next goal. In fact, I would argue happiness is the beginning of all activity because once something gives someone happiness, they work hard at that one thing to achieve the feeling of happiness again. Furthermore, I only partially agree with the statement that happiness is not a state but an activity. Dictionary.com states that an activity is "a specific deed, action, function, or sphere of action." So by this definition, it isn't exactly clear whether happiness is an activity. Allow me to elaborate, happiness definitely isn't an action, because if it were an action, it would be something we would all carry out on an everyday basis. However, if we take the latter part of the definition, happiness can be a activity because happiness is a function of all the different things we achieve, do and accomplish. If one does nothing with their lives, their happiness is going to be a function of that inactivity. And consequently, if one really does strive to achieve a lot, their happiness will directly be affected by all that activity.