The playstyles thing for me is just the social contract. I put mine in Stone Halls & Serpent Men, but I’ve been using/refining this forever:

  • Every group should negotiate a “social contract”; the author’s is:
    • Bring your own dice, paper, writing utensils, etc., and don’t touch anyone else’s.
    • Beer or other drinks are OK in moderation, but don’t get drunk at the table.
    • If you say it, your character does it or says it. If you have to discuss rules, say “out of character” first.
    • I don’t mind jokes or quotes at the table (Monty Python is relevant to every gaming situation), but keep it on-topic. “I don’t want to get on the cart!” is fine when the players are dragging your mostly-dead body around, singing the Philosopher Song is probably not, talking about TV is right out.
    • No party infighting. Unless I have replaced your character’s brain with a parasite, you don’t fight other PCs. Making new PCs, getting them back to the adventure, soothing hurt feelings, it’s a total waste of time.
    • No bards or other nuisance characters. If you think what you’re doing would annoy other players, don’t do it.
    • Every problem I present can be solved with at least two options of violence, sneakiness, puzzle-solving, and politics. Try not to use violence first all the time.
    • Don’t dare me to kill you, because I will.

Other than that, I pretty much expect PCs in the “heroes for hire” to murderhoboes range, occasionally well-intentioned supervillains; I’ve never seen a group of actual goody-two-shoes heroes, and I’d probably run in terror from such freaks.

I run a sandbox full of weird stuff, but will drop things in the PCs’ way which may be rather obviously “tonight’s adventure”. They can walk away, but I’m under no obligation to think up something better than random encounters if they do.

Once in a long while (every score of sessions?) I do a videogame-like cutscene session with some railroaded dialogue in between a few player choices, if I can’t find a better way to dump exposition; I’d like to avoid these but sometimes it happens.

When I’m doing solos, that’s a different matter, usually completely isolated sessions with the same chars, or a sandbox map with semi-randomized encounters (which I may eventually publish).