A knowledge that another has felt as we have felt, and seen things not much otherwise than we have seen them, will continue to the end to be one of life's choicest blessings.
"I can see nothing," said I, handing it back to my friend. "On the contrary, Watson, you can see everything. You fail, however, to reason from what you see. You are too timid in drawing your inferences."
When the only bond between close friends is attachment, then even a minor issue may cause one's projections to change. As soon as our projections change, the attachment disappears, because that attachment was based solely on projection and expectation. It is possible to have compassion without attachment, and similarly, to have anger without hatred.
If friends disappoint you over and over, that's in large part your own fault. Once someone has shown a tendency to be self-centered, you need to recognize that and take care of yourself; people aren't going to change simply because you want them to.