I think it is like the way getting married is statistically more healthy.

Friends and a partner act like a small life coach. I am sure many unhealthy habits are correlated with being left entirely to your own devices. I know I would go to the doctor more if I had a partner coaching/bugging me that I go more.

We are the outliers. If everyone was wired like me, the concept of a dinner party would simply not exist and Facebook would look like this.