Survey: What do you want from other people at the table?

[Private-Prinny]

A few questions about tabletop RPGs, if you have the time. I'm asking about personal taste, so don't be afraid of talking about what you like instead of what you think everyone likes.

1a: When you're a player in an RPG, what's the best thing for your fellow players to be doing?
1b: What should they never do?

2a: When you're a player in an RPG, what's the best thing for your DM to be doing?
2b: What should he/she never do?

3a: When you're DMing/running an RPG, what's the best thing for your players to be doing?
3b: What should they never do?

1a: Flesh out their character and contribute to the campaign as a whole. D&D is a group game, so the whole group should be involved.
1b: Conversely, they should never try to actively sabotage the party, or start PvP without party consent.

2a: I like my DMs to have a plan. The further ahead they're thinking, the better. Encounters can be much more fun if the DM has a specific goal in mind compared to a random statblock fetched from the Monster Manual.
2b: The DM should never actively try to destroy his party. Note that challenge =/= destroy, and unwinnable fights can be fine if none of the characters actually die.

3a and 3b are effectively the same as 1a and 1b. I wouldn't want my players making things less fun for anyone else involved, or actively try to destroy the campaign I'm running.