From Nate Fick’s book One Bullet Away: The Making of a Marine Officer:
Two guys in a bar bump chests, get up in each other’s faces, and yell. If a fight follows, it’s about honor, about saving face. That’s posturing. Marines on the battlefield must exhibit predatory behavior. In that bar, a predator would smile politely at his opponent, wait for him to turn around, and then cave in the back of his skull with a barstool.