If you have to try to be cool, you will never be cool. If you have to try to be happy, then you will never be happy. Maybe the problem these days is people are just trying too hard.
Happiness, like other emotions, is not something you obtain, but rather something you inhabit. When you're raging pissed and throwing a socket wrench at the neighbor's kids, you are not self-conscious about your state of anger. You are not thinking to yourself, "Am I finally angry? Am I doing this right?" No, you're out for blood. You inhabit and live the anger. You are the anger. And then it's gone.
Just as a confident man doesn't wonder if he's confident, a happy man does not wonder if he's happy. He simply is.
What this implies is that finding happiness is not achieved in itself, but rather it is the side effect of a particular set of ongoing life experiences. This gets mixed up a lot, especially since happiness is marketed so much these days as a goal in and of itself. Buy X and be happy. Learn Y and be happy. But you can't buy happiness and you can't achieve happiness. It just is—once you get other parts of your life in order.