Totally agree. I hate online multiplayer, for me it has limited appeal unless I'm playing with someone I know really well, which sadly isn't possible most of the time. But I really got into what naughty dog have done. You basically have to work as a team, and stay hidden, move slowly and it really captures some of the tension of the single player.
i totally suck at it of course, but its very satisfying taking down someone who didn't see you until you were smacking him with a pipe with scissors taped to the end.