I worked with someone a long time ago who never smiled. Whenever he said something remotely positive I always wanted to say to him, "Why don't you tell your face!"  As it turns out - not bad advice for all us!

Here are three scientifically proven ways to give yourself a happiness boost at work in just a few minutes, according to research presented in the book "59 Seconds: Think a Little, Change a Lot" by Richard Wiseman:

1. Imagine a situation that would make you smile and just start smiling for at least 30 seconds, no matter how stressed or grumpy you may feel. In other words, behave your way to a better mood. Several studies confirm that people who are forced to smile by holding a pencil between their teeth report feeling happier and having a more positive sense of humor. (Grab a pencil and try it. You know you want to.)
 
2. Sit up straight. Studies have shown people in control groups who sit up straight for just 3 minutes are much happier than people who slouch in their chairs! So act your way to a better mood by being aware of your posture.

3. Walk and move in a more relaxed and expressive way. People who purposefully walk with a spring in their step, who swing their arms more freely, and gesture more expressively report feeling much happier - and again, it only takes a few minutes for an impact to be felt on your mood.

The added benefit of acting like you're happy and telling your face and body that you're happy is that it will make you more approachable, likable and attractive to the people around you, which will help boost your mood even higher!