What annoys me is when people don't communicate while playing a team game. I got pulled into a team of 5 active duty marines and I played 3 rounds with them. No one on the team did anything STUPID (really rare) and I learned to call out contacts like they did. We completely and utterly slaughtered all three other teams. It was a great experience.
Everything since then have been downhill on the game. Nice to see our boys getting it done.