Do not make me feel uncomfortable - Do not ask, swear or insult - Do not keep silent (Quiet room is worse) - Do not talk about things that make another awkward - Do not mention anything private, if it's a negative thing. Always say hello (I find it very rude if you come to my room and do not speak to me). Do not be rude and think that this is your room, if you are not on my team.
Don't just watch, be part of the action!