I think that describes allot of people
Always people you care about too it seems.
When I find myself at my wits end with people and actually consider isolating myself from them or writing them completely off as a friend, I basically think and consider that at this point I have nothing to lose in being open and honest about their attitudes and behaviors towards me. Basically saying that if you write them off, your no longer friends, and if your open and honest, which in turns angers them to the point where your no longer friends, its the same end result. You only everything to gain from confronting his/her attitude and nothing to lose.
Also, remember that people tend to really be care free with no "filters" or fears of saying exactly whats on their minds when they a very close to you. They feel safe and probably do not fear just acting themselves. So you as a friend, should actually consider that perhaps a serious talk with them could in turn work wonders, and really hit home with the person. You could help them develop as a person, I bet they respect your opinion more than you think.
Good luck with it, I wish you luck
0ldsoul