Habits that kill fun in a session.

[big teej]

Oddly enough, pacifists can be quite effective if the Book of Exalted Deeds is in play. I remember a game where a player ran a pacifist Paladin, and effectively shut down every combat or converted half of the enemy goblins to our team - when I mentioned the morally dubious nature of using what was basically mind control on enemies, he justified it as a greater good issue. Pretty interesting, actually - the rest of us just adjusted our battle strategy to KO instead of TPK - and I finally found a use for Nonlethal Spell.

The Unwilling
You know this one, I certainly do. This is the girlfriend with no interest in d&d but insists on spending time with her BF during sessions and playing a character. Though we would be willing to accept that she's a new player and teach her the ropes, she shows no interest in the game at all and basically relinquishes total control of her character in combat to him. This, too, would be tolerable if only the entire game didn't grind to a halt every time she had to make a die roll.

Of course, this situation doesn't always apply to girlfriends, that's merely my personal experience.

obviously this may not work for your group.

but I'm up front with players, as soon as they say something like "hey big teej, can my girlfriend/boyfriend/buddy/whatever come play with us?"

my immediete response is "are they going to play or observe?"

if observe, my next question is "will they be disruptive? and what is the nature of their observation?"

if the answer(s) to taht question are "no" and "to see if they like it"
I"m cool with it, they can come.

if the answer is "yes" and "anything else" no, they can't come

if the answer is "no" and "so they can hang out with me" or something similar, I'll tell them to just not show up and go spend time with them.

if "to play" I proceed immedietly to "are they seriously interested, or just humoring you?"

etc etc etc.

tl:dr I no longer permit "unwillings" at my table.