Courtesy of Carmine Coyote at http://www.slowleadership.org/blog/2008/08/how-to-give-up-suffering-the-workplace-blues/
Don’t buy the foolish idea you have a right to be happy and successful. There’s no such right. The best way to be happy is to give up being miserable. The best way to be successful is to be who you are and do what fits with that. Sometimes you’ll feel happy, sometimes sad, and very often neither. That’s the way life is. Smile and enjoy it.
Stop watching your emotions. They’re not worth it. They go up, then down, then up again like the stockmarket. No one really knows why, whatever they try to tell you — not even mental health professionals. You can’t will your emotions go or stay where you want, so quit driving yourself nuts by trying. Best of all, treat them like the weather: sometimes an inconvenience, sometimes a pain, and sometimes full of joyous sunshine. Many of them are probably due more to what you ate or drank yesterday than anything meaningful.