A good observation from The Happiness Project on how to be more energetic and how it will affect others around you.

Energy (or lack of energy) is contagious. If you feel energetic, you’ll help the people around you feel energetic, too. And that makes them feel happier, too. In fact, studies show that being an energizer was one of the strongest predictors of a positive performance evaluation at work.

I buy that.  Think of the best performers in your office.  They probably get a lot done but they are almost always very energetic as well.