Where did this minor rant come from? A discussion of the responsibilities of a GM. Is the GM responsible to the plot or the characters? A few people responded to my rant with an excellent point: GarouMUSH is a piece of collective fiction, and so the GM must have more responsibility to the plot than, perhaps, is usual in roleplaying games. I grant this exception to the rule, but I think that aside from that, my note contained one of the best summaries of my game-mastering style I've managed to put into text.
The first -- and, indeed, only -- responsibility of any Game Master is to the players.
A GM whose first priority is the Story is just an author that's too lazy to write his/her own book. This goes for both larger (MUSH) and smaller (tabletop) scales, no matter what some people may think.
What is the GM's responsibility to the players? To construct a mutually enjoyable experience.
Not to be as "realistic" as possible. Not to garner glory and recognition for a favorite GMPC. Not to get his/her own rocks off by killing characters or tormenting them into unplayable messes. Not for the purposes of self-glorification through personal hardship (read: martyrdom) to "run something for people, since *dramatic pause* no one else will."
To have fun and give fun through performance and mutual storytelling. GMing is a selfless art with a selfish outcome: the pleasure for the self stems from the pleasure given to others.
It is NOT the GM's responsibility to make judgements on the actions and/or motivations of the players. OOC actions do NOT engender IC consequences.
If a combat starts out with 15 players and drops to 5 players through attrition due to the lateness of the hour, network difficulties, or even player selfishness, it is the responsibility of the GM to keep the combat fair and enjoyable for the remainder, whether through deus ex machina, the bad guys finding something else to do (to be thought of and explained later), or by providing a clear escape route if he/she isn't willing to compromise his/her Story.
The GM mandate is, however, compromise.