You can't change someone's personality but you can darn well make it clear that certain behaviors resulting from that personality won't be tolerated.
There's a small restaurant/bar near where I live that serves great fried chicken. The chicken is excellent and the location of the place makes it a great hangout for the locals. But the problem is, it's run by a guy we like to call the Chicken Nazi. I'm not sure if he has a personality disorder or just woke up on the wrong side of the crib all those years ago, but he's the rudest, grouchiest person I've ever met. It's fairly common to see one of his waitresses crying. He's not much nicer to his customers.
Yet he stays in business year after year. Is the chicken that good? Is the camaraderie among the regular customers so valuable that everyone is willing to overlook this cretin? Yes and yes. Frankly, I wonder why one of those waitresses hasn't popped him upside his head by now. I'm not advocating violence, but I think at some point something has to be done to show this guy that he can't get away with his bad behavior.
I'd venture to say that all of us at some point have encountered a co-worker who, for some reason, is perennially excused for bad behavior. That person might have some quality that seems irreplaceable-he's a mad coding machine, a gifted IT troubleshooter, a moneymaker-so everyone just works around the less desirable qualities.
In these situations, the emotional burden falls on that person's co-workers. It is the coworker who has to endure the temper tantrums and the arrogance toward end-users, or who has to sit by as the "gifted" employee monopolizes meetings with attention-seeking monologues. I just don't understand why some of these behaviors are allowed to continue.
Managers should not make exceptions for rude behavior by employees. You can't change someone's personality but you can darn well make it clear that certain behaviors resulting from that personality won't be tolerated. Managers should deal with poor attitude and bad behavior as promptly as they would behavior that costs their company money.