What Are Friends For?

One of the main questions i have never been capable of answering is: what are friends for? Maybe someone can help me. Being too friendly are issues such as never saying no and giving people too many chances after they have messed up. Often people think they're being used and they get upset. But don't we all use someone or get used? If I asked a friend to pay for something, or take me somewhere, or even borrow some money I would be using them for services i want or need. Using is not always bad because the deeds I just listed were examples of a friend doing a good deed for someone else. But in a way i'm still using him or her. But have you ever been called mean or not friendly or fake? People often called you these things when they ask you for something and they don't recieve it. But you can't automatically label that person as fake or mean if you don't get what you want out of that person can you? You can come to the conclusion that these people are trying to use you for your services and are not very fond of being told no. So the question comes up again;what are friends for? To talk about personal things? To be there for you when they're sad? To pay a couple of bills when they're struggling? All of these are true, so it's safe to say that the only thing friends are for is to be used...right?