The way to happiness in life is to let go.
This is easier said than done as posessivness is part of us.
However once I let go I find it was not worth the anger and frustration.

One other the thing what the almighty does he does for good.
So if it is was that girl,job etc that you desired and you didnot get it was probably what the almight thought best for you.
What is that proverb .....Don't Wish To Hard You Might Just Get What You Wish