There's a scene where Moss is trying to elude Chigur from a hotel, and so he decides to stop this guy in his truck and try to get away, but Chigur shoots the guy driving the truck in the neck and forehead with such precision that we are led to believe Chigur is pretty much a sniper. Why then, didn't he take out Moss, who was in the same truck? If he took out Moss, the other guy was just some shmuck who he wouldn't have to worry about, or killed him right after this, so who cares?
EDIT: Holy shit, there are so many plot holes in this movie, I think I don't like it anymore.