You are what your friends eat
Memes worm their way through social networks to reach populations in surprisingly little time. It seems mood and obesity are two phenomena transmitted — like memes — by networks of friends. When it comes to happiness (and weight), we are what our friends eat.
Given the amount of time spent and the importance of relationships with close friends, it makes sense that certain aspects of life are socially contagious. We’re social creatures; much of what we do and who we are is influenced by those in our network of connections, from our spouse and closest friend to our colleagues and neighbors.