These are some quotes out of the liner notes from the 'Who Cares A Lot" greatest hits.  If you want to read the whole thing (and it is a really cool read) I found it online here- http://www.angelfire.com/pa3/fnm/FNMbio.html  But here's some of the stuff about them not getting along.
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Typical stuff. You see, Faith No More were often an obstreperous pain in the arse. Even when things looked like being peachy-creamy, it always seemed that one wheel had to go wonky if only to maintain their status quo. It's a miracle they made it beyond 1988, having spent the best part of three years prior shoving themselves into Ryder trucks (sleeping bags and pillows included) for national tours, with tempers often fragile in such gerbil-like close quarters.

Most bands last out stuff like this by being close friends. Not here. The truth is that much of Faith No More's longevity and creative magic revolved around thick, fetid, repeatedly denied tensions. Some were obvious: the escalating piss fights with Mosely in the mid to late '80s, the disgust and dismay at Mike Patton's stubborn refusal to place Mr. Bungle a spiritual second to his FNM duties, the sheer anger between Jim Martin and the other four until the breaking point in 1994. But most days there was something bugging someone somewhere. I know they never agreed that tension was a vital ingredient of their resultant sound, and probably still wouldn't, but during the band's richest spells of creativity and commercial popularity, they were always in some form of self-induced turmoil. Secretly, they held high regard for each other's talents, but sadly said it enough.

When they first visited Britain in 1987, they did interviews where they'd rip the shit out of each other to the utter astonishment of journalists, making anything the Gallagher brothers from Oasis have engaged in seem like quaint foreplay. It was tough to tell if they were joking or using interviews as the medium through which to talk to each other. Martin once told me that Mosely was like an irritating pimple being rubbed by cheap ladies underwear...Mosely was five feet away. Patton used to loudly hawk demo tapes of his then unsigned band Mr. Bungle within generous earshot of others. And when the "Epic" single hit the American top ten in 1990, rather than celebrate, they complained loudly about what a big bunch of bullshit it all was because they weren't seeing any dough, only airports.
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That's because Faith No More only ever did what they wanted, despite the polar opposite personalities within the creative process. Gould was a quiet pressure cooker who would blow his stack every few months in spectacular fashion; Bottum was the floating carefree sort; Bordin would go wherever the comfort and ease of passage seemed greatest; Patton seemed to enjoy the thrill of pissing everybody off in any way necessary; and Martin would often belligerently refuse to entertain his bandmates, just because. Compromise was the equivalent of profanity in church,
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Everyone would marvel at Bordin's curious penny-pinching habits, which once went to the absurd length of trying to exchange some free shoes for another pair at some sportshop in the next city during the band's Billy Idol tour in 1990. Patton would talk shit about everything and everyone for awhile, seemingly delighted to plant such seeds of insecurity. Bottum's lifestyle and interests saw him drift away from everyone in the group, and Martin was an outright antagonizer, jabbing a boney finger into what he saw as an open wound that was being left untended. Billy Gould, a mischievous master of experimentation, unwittingly found himself in a "den mother" role he carried to the band's last day.