Vocalists AND guitarists.
8 piece Funk band, two female singers. One would shriek every time she made a fluff/mistake, even when gigging; that drove me insane! Guitarist in same band was a massive Prima Donna who (annoyingly) cultivated a faux-gay persona and went in the huff every ten minutes. Those two quickly became an item and then started travelling separately to out-of-town gigs. Division ensued, becoming an 'Us and Them' camp. They eventually left the band and drifted off into musical oblivion.
Then there was the male vocalist who was obsessed with Elvis and used to pull crap, Elvis-style karate moves on stage, often losing his balance when doing so. Totally cringeworthy. At times I was thankful for both my position near the drum riser and the fogger that occasionally hid my disapproving countenance from the punters.
Two guitarists in another band became hooked on heroin and consorted with the (serious) underworld figures they were buying it from. They became completely unreliable fast, and were two of the most accomplished fabulists I have ever met! One time, they rocked up hours late for a rehearsal. Their excuse? They had gotten us a gig! In a brothel! I shid you not!! Both eventually succumbed to the demi-monde they had been sucked into and did time; they were also rumoured to be police informants. A shame, for they wrote some good tunes!
Female vocalist channeling Janis Joplin. Good Blues shouter who would, out of the blue, make random, disparaging comments onstage about some of our original numbers. Go figure.
Female vocalist channeling Stevie Nicks, complete with wardrobe but, thankfully, sans private off-stage tent and substances. A lovely girl with stars in her eyes who couldn't sing for her supper and assured us that 'RCA/Arista/Polydor/Sony are at this gig tonight!' at every gig!
Then there are the drummers. But I'm not going there. Yet!