This decline in real friendships and the resulting loneliness we experience are not without cost. Medical researchers and social scientists have pointed out that a strong link exists between friendship and well-being. People with close friendships tend to have better health, are more fulfilled, and live longer. The village of Roseto, Pennsylvania, contains a close-knit community of Italian immigrants who frequently stop to chat on the street, visit with one another, and even cook for each other in their backyards. Researchers who have studied this village have shown that people end up living longer if they stay in Roseto than if they move away. This increased health and life expectancy wherever there is a strong sense of community has been coined "the Roseto effect."

Strong friendships also can make a difference in our psychological well-being. In 1937, a researcher at Harvard began a long-range study on the key factors that contribute to human well-being and happiness. The study tracked a group of 268 men who entered Harvard College in the late 1930s over the course of seventy years. The researchers followed them through their life experiences: war, career, marriage, divorce, parenthood, grandparenthood, and old age. One of the things that surprised these ambitious, elite men (now in their nineties) as they looked back over their lives was the fact that it was not their career successes nor their celebrated accomplishments that brought them the greatest satisfaction but their relationships with family and friends.