We briefly had a "lead guitarist" in our band. (Our other guitarist, that I started the band with, sings lead and basically plays rhythm, other than solos and such). He was actually a very good guitarist, but he was a jerk to deal with. He always wanted to change songs, and wanted to be the "star" of the band. He actually told my singer one time "we need to decide who is going to be the star of this band." He would also bad mouth everone in the band behind their backs, talking about how people weren't playing well enough, etc. I think he felt we should be playing like Primus or RHCP, rather than a local four piece cover band.
The main problem though was that he wouldn't stick to a set list, or stick to the way a song was laid out by the band. We did one and only one gig with him, and he just went off into solos whenever he wanted, broke into songs the band hadn't even rehearsed, etc. He would also have his Line 6 amp cranked WAY too loud all the time, and would always blame it on the amp, saying "it's digital...it's just turning it's own volume up." Then he'd make up some BS about how he had to have a technician hook it up to a computer to fix it, and how that would cost $500, etc. It was total crap. Speaking of money, he also tried to get us to help him pay for his rather crappy Crate PA system, which he had bought before any of us had even met him. (He was on some stupid payment plan with the guy he'd purchased the PA from) "Um, no, sorry...", we told him.
Finally, after yet another practice where he had his amp cranked way too loud, so loud that the drummer could barely hear himself playing (!)...he went home after practice, and the next day when he came to pick up a certain piece of equipment, all his gear was waiting for him out on our singer's lawn.

Our singer fired him right then and there. He was pissed, apparently (I wasn't there, the singer volunteered to fire him himself), because he was that tired of his garbage), but he had to accept it at that point at least.