A study in The British Medical Journal has shown that happiness actually spreads from person to person, up to three connections away. "So if your friend's friend's friend becomes happier, it ripples through the network and affects you, even if you don't know that person," says author Nicholas Christakis, MD, a medical sociology professor at Harvard Business School.

Proximity plays a part: A happy sibling who is a mile a way can increase your probability of happiness by up to 14%; a nearby friend by 25%; and a next-door neighbor by 34%.

The effect also applies to smoking and obesity. According to Christakis, "If people around you gain weight, it changes your expectations about what an acceptable body size is. Our work strongly suggests that when one person quits smoking, loses weight, or becomes happy, others around her follow suit. I am reluctant to suggest you pick your friends solely on this basis, but one could say that helping a friend do better is a roundabout way of helping yourself."

So, create a happy day and watch the ripple~~~~~~~~