I was involved in a very nasty one a couple of years ago.
Was going to write the long version of this, but it's not that interesting unless you were there.
Had a GM had a real gift for description and dialogue. Ran some really fun games, but over time the players got more and more hacked off with the bad stuff. It's a full list:
Heavy railroading.
NPC favouring house rules. Introduced mid combat.
Every campaign had 1 or more players with an anti party backstory. - 9/10 it was his wife.
Stratospheric body counts for the other 'less important' characters.
Cthulu mythos in every single game.
All started as minor things and grew worse over the years.
Further compounded with differences in what the players and GM wanted. Players wanted heroic tales. GM wanted lethal survival horror. Differences grew more marked over time.
We tried talking to him about it at the correct times. i.e. when we wern't playing. It was all dismissed as 'whining' and nothing changed. Couple of players even ran short campaigns showcasing what they were talking about - he enjoyed them, but never changed anything.
Came to a head at the finale of a particularly bad adventure. An adapted module that was really badly written. Ton of backstory, but the players never get to find any of it out. Reads like a lot of fun, sucks to play. Ended in a TPK, bought about by a backstabbing PC.
Ended up with a pitched shouting match between players and DM. Everyone parted on bad terms and the players went off and started our own group. He's been back in touch lately wanting to run a new game... I can remember the good bits of his games and they were really good... Part of me wants to say - 'not before hell freezes over' and another part is curious to see if he's changed.
Right. That did go on a bit. Apologies.
