Happiness for me is life in general as heck, I'm a happy-go-lucky person. I'd say that I'm happiest when I'm with my friends and they're all having a good time. So I guess you could say for me, happiness is life, is singing, and when I see other people being happy. That's happiness for me.
Runner up would be cosplaying as Edward Elric...I get to chase people who call me short...hurray for being the exact same height as Ed a.k.a. 5'2"?