I expect my players to entertain me via what they have their PCs do or say, and the personalities they give said PCs. In return I feel they have a right to expect me to entertain them with the game I run.
Beyond that, nothing much matters.
All good to here.-Don’t smell
-Don’t cheat (whether by dice or rules "mistakes")
-Show up on time
-Be ready on your turn
-Engage with the DM’s world
I'm on the fence on this one; as I don't mind if the players/PCs decide to go off and do something I don't see coming. In fact, I see it as a sign of decent engagement with the DM's world if they do this rather than just tell me my plot sucks.-Don’t purposefully tank the DM’s plotlines (I'm not going to railroad you, but don't try to sabotage my campaign, either)
I'm over the fence on this one; anything goes here, with the known-by-all proviso that what goes around comes around...-Don’t cause trouble with other PCs
All good to here.
I'm on the fence on this one; as I don't mind if the players/PCs decide to go off and do something I don't see coming. In fact, I see it as a sign of decent engagement with the DM's world if they do this rather than just tell me my plot sucks.
I'm over the fence on this one; anything goes here, with the known-by-all proviso that what goes around comes around...
Lanefan
I suppose I should instead say “group goals” rather than “DM’s plotlines.” I can improvise and adapt, but when a player just says “no, I don’t want to do the thing” after the entire group said “yeah, let’s do the thing!” that makes my job a whole lot more difficult.
Nothing is more infuriating then players NOT acting in character as their PC would. You don't have to use various voice accents, but please play your PC as if you were the PC.
I realize this is a very subjective question but I'd be interested in hearing whether people think the players have any responsibility for their GM's fun and if so what the responsibility of players are when it comes to their GM having fun and enjoying the game.
When the rest of the players decide to go into a dungeon, and one player says their character isn't going in, it is not the GM's problem, in fact rewarding that one player with one on one gaming disrespects the other players. It has happened to me as GM, and I've looked at the offending player as "really?"

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.