In my experience the lack of or the existence of happiness is a result of slight changes in perspective. The lack of something, the failure to gain what we think we desire or need, is many times the opposite of emptiness- nothingness has matter and matters. When I fail it lacks finality. Failure is never final. Emptiness is never empty. I gain by losing. I gain by winning. So in the end I am happy with nothing because i know that nothing is just a moment on my path. My happiness comes from journey on that path and not any one singular dot along that path.