Not just happiness. I hate when people say happiness, when they mean many other things. Happiness isn't everything; this experiment is still true for those who realize that seeking only happiness is shallow. Help others, and you gain much deeper things.
This movie had such a deeper storyline and played out on a far bigger global scale the the movie truly shows. They say the closer you look, the less you'll see, but the truth is that the closer you pay attention, the more you will expose.