Of Mice and Men blog:2

"What makes a friend? Why do we have friends?"

The definition of a friend is a person whom one knows and with whom one has a bond of mutual affection, typically exclusive of sexual or family relations. A friend is a person that you can go to if you are having problems with something or someone, and they will tell you what they think, or they’ll just listen to what you are saying so you can get it off of your chest. It is also someone who doesn’t really judge you for what you do, and will accept you for who you are. Something people need to remember about friends is that they change over time, and you might lose some, but you might gain some at the same time. It’s really hard to stay friends for a long time because people change, and you lose contact, but you might become friends with them again in the future.
We have friends because we usually want to be able to depend on someone without getting judged and know that they will be for you when you need them or they will at least try to be.