Hey people, nobody has given a serious advice yet..
Alright then. Story time;
I had a guitar player for the entire 1990's and into the 2000's that was a real jerk. Egotistical may not be the right word, but he was certainly opinionated, and his way was definitely the right way. He got on my nerves like crazy for the first 5 years or so we played together. There was one night that I came very, very close to knocking him off of a very high stage because he was being a jackass on stage.
That was the breaking point. I sat him down afterward, and we had a little discussion. I told him that he was a very talented guitar player, but his people skills sucked (that's verbatim). I also told him that I had very seriously considered kicking his ass off the stage ten feet to the ground.
He apologized! He said that he was in fact aware of the fact that he had a very grating personality, was a perfectionist, and people thought that he was an *******.
We actually got to be friends after that! When he would start getting all *******ish, I would stop and tell him that he was being a jerk. He knew that he had personality flaws, but he didn't understand what they were. He's still kind of a prick, but if he gets out of hand I just tell him he's being one, and he attempts to stop.
Part of the issue is that he has a very weird sense of humor, and people take his sarcastic caustic remarks seriously. He thinks he's being funny half of the time.
So I guess the moral of the story is; You can't fix someone elses personality flaws, but sometimes it doesn't hurt to be sure they are aware of them.