State of Play: The Impossibility of Teamwork

There is nothing more rage inducing to me than failing to do something in a game thanks to the complete lack of cooperation from a fellow gamer. Or to be more precise, when I die because of XxXSniprnoobz420XxX over there didnt bother to turn around when his motion sensor showed there was an enemy coming around the corner. Why is it so impossible for the general gaming population to think or act in a manner that could loosely, in the most vague of definitions, be seen as teamwork?

Most of us have been there, a tense situation whether it be a boss fight with your party, a gunfight against the enemy team, or trying to train enough marines to hold off a zergling rush. You look to your fellow gamers for aid that would take them half of a second to complete yet they continue to just run into the wall, have 6 snipers on a team of 7 players, or continue to gather resources and ignore the incoming invasion. They make an effort to hurt to the team as a whole by ignoring everything that does not involve them helping themselves, and even in games where they can benefit by helping others these players manage to find a way to hurt both themselves and every other unfortunate meat bag randomly assigned to his or her team.