Even if you've got your dream job (and especially if you don't), work isn't always fun. A combination of stress, overwork and tough breaks can leave even an optimist feeling down and out. And if you're not naturally an optimist, it's all too easy to "get the blues."

When you're feeling sad, it's difficult to accomplish much, which in turns makes you feel worse. If you're not careful, you can create a downward spiral that blows away an entire day or even an entire week.

What's worse, if you're down, you'll pull other people down too, because sadness is highly contagious. Being able to pop yourself out of a sad mood and into a positive mood is thus an essential skill for anybody who seeks either personal or team success.

I learned the technique described below from my mother, a high-powered salesperson for Bristol Myers. I've since learned the neuroscience behind why it works, but what's important is that it works, consistently and easily.

1. Sit up and smile

Like all strong emotions, sadness is part mental and part physical. When you think sad thoughts, your brain throws your body and face into a posture and expression of sadness. Your posture and expression, in turn, signal your brain to think sad thoughts.

To interrupt this feedback loop straighten your back so that your posture is upright but relaxed, keep your head high but with neck muscles loose, and put a relaxed smile on your face. You will immediately feel better.

2. Disconnect, distance, distract

Now that you've interrupted the physical part of feedback loop, it will be easier for you to redirect your thoughts away from whatever is making you sad. To do this, use the 3 Ds:

  1. Disconnect. Rather than telling yourself "I am sad" or "I feel sad," repeat to yourself: "I'm doing sadness. It's my decision whether or not to continue."
  2. Distance. Imagine that you're viewing yourself from a mile away, like you're a picture in a tiny television screen.
  3. Distract. Focus on something that's completely different and separate from whatever triggered your sadness.

3. Take a walk

By interrupting the feedback loop, you've given yourself some emotional breathing room. Use that time to further break the physical component. Stand up and walk somewhere. keep the upright posture and breath deeply.

Ideally, you should walk somewhere away from the office, but even a spin around the cubicle farm will work. While you're walking, continue with the 3Ds. Every time you reach "distract" try to dwell on the distraction.

4. Thank somebody

To keep your sad thoughts and physiology from returning, focus your attention away from yourself and towards somebody else. The best way to do this is to thank somebody who doesn't expect to be thanked.

In every workplace there are people who contribute in small but important ways but who are never, ever thanked: receptionists, cleaning staff, lunchroom workers, accountants, lawyers, tech support, etc. Brightening their day will brighten your own.

5. Help somebody

At this point, you'll already feel more positive and upbeat. Give those happier feelings more momentum by finding a way to help somebody else who's struggling at their job or obviously suffering under extra stress.

There are few questions more welcome in the workplace than: "Hey, can I give you a hand with that?" What's more, when you're making a positive difference in someone else's life it's almost impossible to feel sad and exceedingly easy to feel happy.