Talking to your neighbor may extend your life
Researcher Julianne Holt-Lunstad studied tens of thousands of middle age people. She looked at their diet, exercise, whether they smoked, etc. The #1 factor that reduces your chance of dying is social integration — how many people you interact with through the day — this includes your family and friends as well as casual contact with strangers like the mailman or saying hi to a neighbor.
Susan Pinker gave a TED talk about this research.