Aristotle's take on friendship

"In poverty as well as in other misfortunes, people suppose that friends are their only refuge. And friendship is a help to the young, in saving them from error, just as it is also to the old, with a view to the care they require and their diminished capacity for action stemming from their weakness; it is a help also to those in their prime in performing noble actions, for ‘two going together’ are better able to think and to act."

• Friendship of utility
• "this accidental friendship is two parties are not in it for affection. Rather, they’re in it for the benefit each receives from the other. These relationships are temporary: whenever the benefit ends, so does the relationship. Aristotle observed that these relationships of utility were most common among older people."
• Friendship of pleasure
• "this accidental friendship is based in pleasure. This kind of relationship, he found, was more common among younger people."
• Friendships of virtue
•  "take time and trust to build. They depend on mutual growth."
•  "is based on a mutual appreciation of the virtues the other person holds dear. In this kind of friendship, the people themselves and the qualities they represent provide the incentive for the two parties to be in each other’s lives. "

Reference: Life is too short for shallow friendships