Must Read:
"Two weeks later I had an epiphany. It changed my life, and I hope it's changed the course of psychology. I was in my garden with my five-year-old daughter, Nicky, and to make another confession, even though I've written a book about children and have worked with children, I'm no good with them since I'm time-urgent and task-oriented. I was weeding, and Nicky was throwing weeds into the air, dancing, singing and having a wonderful time -- and I shouted at her. She walked away, puzzled, and walked back and said, "Daddy, I want to talk to you."
I said, "Yeah, Nicky?"
And she said, "Daddy, do you remember before my fifth birthday" -- she had turned five about two weeks before -- "I was a whiner? That I whined every day?"
I said, "Yeah, I remember -- you were a horror."
"Have you noticed since my fifth birthday, Daddy, I haven't whined once?"
"Yeah, Nicky."
And she said, "Daddy, on my fifth birthday I decided I wasn't going to whine any more. And that was the hardest thing I've ever done. And if I can stop whining, you can stop being such a grouch."

From Martin Seligman's Eudaemonia, the Good Life, and a whole lotta tests and questionnaires to ascertain our Authentic Happiness :-)