My dog is probably one of the happiest creatures I know. But he can't get his own dinner and I have to take him out to poop.

If everyone was happy all the time we would probably still live in caves because there wouldn't have been the struggle that brings us to where we are.

This in my opinion may be why religion correlates with happiness. For the very same reason lobotomized people might be happy. Do you want to be happy or do you want to know how the world really works and what is certainly going to happen?

But... the dark cynicism of reality aside, I think happiness probably results very simply from good health, physical activity, strong social connections and a feeling of being important or succeeding. It's good to be happy sometimes. But I still think being happy all the time might not be the best thing for us personally, nor for us as a species. IMHOP.