" Most human virtues, I would argue, are social virtues. To the extent that we care about love, justice, or kindness, we care about how people enact these virtues with respect to other people. No one is interested in whether you love yourself, whether you are just to yourself, or whether you are kind to yourself. People care about whether you show these qualities to others. And so friendship lays the foundation for morality. "

― Nicholas A. Christakis , Blueprint: The Evolutionary Origins of a Good Society