Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful.
I love this quote, but I think writers too often misinterpret this sort of thing as meaning if you love it, then money and fame and perhaps a National Book Award or two will definitely come. Not so, of course, there are too many other factors (from talent to timing to the mood of the market to luck itself) to guarantee anything of the sort, but I think that living a life you love is the definition of success.
Besides, joy shines through art, whether it's writing, music, dance, teaching, or what have you. And people respond to that joy, leaning toward the light.
Maybe it won't necessarily bring you world domination, but satisfying, meaningful work is a reward unto itself.