+1!
TopShelf2010: Playing random players you just never know what you are up against.
Also do you not know how the other sees you.
On the surface he sees an avatar on his computer screen, necessary to play the MP game he chose. Will he be willing to acknowledge that there's another human at the opposite screen and show the couth to respect him? Quitting is not much more than switching off the TV.
Making online friends to play with them is a relationship, a delicate one of course, and becoming co-members provides stronger bonds "behind the common banner". Social conventions come into play, making quitting an unfriendly act to avoid.