I don’t play competitive multiplayer games very much, because I just don’t have the dedication to hone my skills to even the median average of the online pack, at least beyond about week 2 of a game’s release, but one thing that’s constantly annoying when I do is people who disconnect because they’re losing. Given that I don’t win online very much, I don’t encounter this that often, but on the few occasions where I’m getting the upper hand, there’s nothing more annoying than having people quit out on you mid-game.
I finally got chance to play Left 4 Dead co-op with my wife rather than single player with all AI teammates, and it’s an entirely different experience. I’d heard this of course, but even so I found it surprising just how much difference it makes. Having a real person yelling for help as they get jumped by a hunter after hanging back behind the others, running scared from a marauding tank together, or frantically trying to help a team-mate up so you can get back up into a defensive choke point before the wall of dead flesh that’s charging down the abandoned subway track crashes over you, it’s simply enormous fun.