From Do Your Friends Actually Like You? – The New York Times:
…Because time is limited, so, too, is the number of friends you can have, according to the work of the British evolutionary psychologist Robin I.M. Dunbar. He describes layers of friendship, where the topmost layer consists of only one or two people, say a spouse and best friend with whom you are most intimate and interact daily. The next layer can accommodate at most four people for whom you have great affinity, affection and concern and who require weekly attention to maintain. Out from there, the tiers contain more casual friends with whom you invest less time and tend to have a less profound and more tenuous connection. Without consistent contact, they easily fall into the realm of acquaintance. You may be friendly with them but they aren’t friends.
But friendship requires the vulnerability of caring as well as revealing things about yourself that don’t match the polished image in your Facebook profile or Instagram feed, said Mr. Nehamas at Princeton. Trusting that your bond will continue, and might even be strengthened, despite your shortcomings and inevitable misfortunes, he said, is a risk many aren’t willing to take.
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So it’s worth identifying who among the many people you encounter in your life are truly friends. Who makes time for you? Whose company enlivens, enriches and maybe even humbles you? Whom would you miss? Who would miss you? While there is no easy or agreed upon definition, what friendships have in common is that they shape us and create other dimensions through which to see the world. This can be for better or worse depending on whom we choose as friends. As the saying goes, “Show me your friends and I will show you who you are.”