Pick who you work with very carefully. Because you are likely to become like them. So the first thing is to know what's important to you about you — what you want to become. What you like about yourself. And then, surround yourself with people who match your aspirations for yourself.

Here are some ideas:

Choose people who are good-looking, but not better looking than you.
You become like the people you hang out with, according to Nicholas Christakis, a physician and sociologist at Harvard. He found, for example, that if the people around you are overweight, you are likely to join them. And the more overweight you are, the more trouble you have at work, for a lot of reasons, but a new reason I just found is that in stressful work situations, fat people do not think as clearly as thin people. Yep. That's right. Stonybrook University School of Medicine found that the more body fat you have, the higher your levels of cortisol, a stress hormone that hampers cognitive abilities. (Hat tip: Self magazine.)

But if the people around you are models, you will look ugly. Dan Ariely, professor of behavioral economics at MIT, says that if you're going to a bar, you have the best chances of getting picked up if you go with people who are almost as good-looking as you are. It makes sense that you will feel best if you do this at work as well.

Choose women who are happy, but they shouldn’t smile too easily.
This is hard for men to do. Because men are hard-wired to be drawn to women who laugh at their jokes. Men want to be funny. But women who are slower to smile do better at work, according to communications consultant Leil Lowndes. So you should date women who smile a lot, but work with women who don't. (Hat tip: Derek Scruggs.) Read more