Happiness is a state of mind, which can be activated by positive emotions.
I guess what you mean is, " What makes you happy the most often, and do you know what it is? "
Mine would be not of physical value, but of mental and spiritual value that would make me truly happy. Creating is always something that I loved, because it involves not just the physical plane, but the moral plane. It helps me reflect on myself, while also figuring out what use it is. Funny, I always seem to question a thing and it's purpose. Must be why I like to dismantle things.