This came across the newsire earlier this month.....
In a study published online today in the BMJ, scientists from Harvard University and the University of California, San Diego, showed that happiness spreads readily through social networks of family members, friends and neighbors. Knowing someone who is happy makes you 15.3 percent more likely to be happy yourself, the study found. A happy friend of a friend increases your odds of happiness by 9.8 percent, and even your neighbor's sister's friend can give you a 5.6 percent boost. "Your emotional state depends not just on actions and choices that you make, but also on actions and choices of other people, many of which you don't even know," said Dr. Nicholas Christakis, a physician and medical sociologist at Harvard who co-wrote the study. The research is part of a trend to measure well-being as a component of public health. Scientists have documented that people who describe themselves as happy are likely to live longer, even if they have a chronic illness.
So as I have often said in my books and keynote speeches- be careful who you associate with it can affect your life. Now we have scientific proof!