Aristotle explored this long ago, mapping out levels of friendship: 1) Friendship of Utility: Affection is based on usefulness, and if usefulness fades so does

Aristotle explored this long ago, mapping out levels of friendship: 1) Friendship of Utility: Affection is based on usefulness, and if usefulness fades so does the relationship. 2) Friendship of Pleasure: Affection is based on pleasant enjoyment of the other, often in shared circumstance such as sport or hobby. When the enjoyment changes or circumstance ends, so does the relationship. 3) Friendships of Goodness: "Now those who wish well to their friends for their sake are most truly friends; for they do this by reason of own nature and not incidentally; therefore their friendship lasts as long as they are good- and goodness is an enduring thing." #1 and #2 are common, #3 is rare.