When it comes to our physical and mental health, friendship may truly be the best medicine. An Australian study showed that strong social networks may lengthen survival in elderly men and women, with good friends being even more likely to increase longevity than close family members. As author Edna Buchanon put it, “Friends are the family we choose for ourselves.” A good friendship is something to savor and protect. Yet, like any human relationship, even our closest of friendships can unravel in moments of weakness.