Green guys are your teammates in a Call of Duty game who are not part of your party: they show up as green triangles on the minimap, as opposed to party members who show up as blue triangles. In other words, green guys are pubbies who are probably useless if not actually a liability to you.
Fucking green guys keep following me around and getting me killed!
In reference to Call of Duty. These are players who are not in your party, and most likely random fools. They are the best players....... FOR THE OTHER TEAM. Usually the reason you are getting shot in the back, noob tubed, or killed by a killstreak, thank your local green guy.
Fucking green guys, get the fuck away from me; Find a corner and STOP FUCKING DYING!!!!!