Why Pursue Happiness?

It has become an expected theory that human beings are supposed to strive for happiness. It makes sense doesn't it? What else would be the goal of our short lives? Even if we become exceptionally wealthy or powerful, what is the point if we aren't happy? It seems though that since the beginning of time, nobody has been able to formulate a blueprint on how to become "happy". Even stars, who are looked up to as deities, don't seem to be happy. What if being happy is only a temporarily felt emotion that cannot be maintained? If we hear that we are going to be parents, or if we get promoted, or even if our sport's teams win, don't we feel happy? Is that what happiness is supposed to be or are we just being stimulated by something exciting? Also, why can't we maintain that stimulation? Well, maybe we should pretend for a moment that obtaining ideal happiness is impossible. Let us pretend that we live life not pursuing happiness, but just simply accepting it when it comes. I understand that we are much more complex than any other living creature, but it doesn't seem like other mammals live their lives attempting to find happiness. Maybe the only realistic goal that we have is to keep ourselves alive for as long as we can. That has become so much easier though will technology and medical advances, so now we are looking for something else to feed on. Happiness might just be a bonus that we feel we must have. Of course, happiness may indeed exist but should we feel like it is necessary? I want to be happy, you probably want to be happy, so why not strive for it. The point I am making is that maybe we are looking for something that shouldn't be expected. Like anger, maybe it's something that we will inevitably feel from time to time, but won't keep forever.