When Mr. Sorrow comes, do not give him strength by acknowledging his presence. If you feed him with the nectar of your tears, he will stay. He will soon spread all over the bedroom of your life. The minute he arrives, laugh at him that will cheat him of his joy. Then kick him in the stomach. Apply the fists, limbs, and elbows of your will, and throw him entirely out of the chamber of your life. Thus you will win both a physical and a metaphysical victory over sorrow.

~ Paramahansa Yogananda

...from the book "How to Be Happy all the Time"

The only thing that makes the
difference in the way you feel right now
is the thought that you are thinking
right now. It doesn't matter how much
money you've got; there are joyful
people with no money, and there are
unhappy people with lots of money.
How you feel is about how you are
allowing the Source that is You to flow.
So when we talk about the Art of
Allowing, we're talking about the art of
living; about the art of thriving; about
the art of clarity. We're talking about
the art of being who you really are.
--- Abraham