What is Happiness?

The Dalai Lama says happiness is the meaning of life. Sounds good to me.
So what makes us happy? A friend of mine once came up with a convoluted theory to explain this but it just seemed to categorize all our wants and desires and once they were fulfilled then you would be happy.
That doesn't quite explain it to me. After all, we never stop wanting something do we?
Ever felt that there was nothing, absolutely nothing else you could want or desire? It doesn't last and I wouldn't consider it happiness.
I know that not being in control of events that affect our lives makes us unhappy.
So, if we were in complete control, would we be happy?

I know that suicide is the last refuge of somebody that feels that everything is completely out of control beyond any hope and therefore, making a life and death decision is the last desperate attempt to regain control.

So, if everything went the way I wanted it, I'm sure I'd be happy, but is this absolutely guaranteed? Do we need obstacles to teach us the limits of what we can and can't have?

Optimistic people can accept that not everything will always go the way they want it to go and yet remain happy. A pessimist sees every obstacle and justification for their pessimism.
I've never met a happy pessimist.