She leaned forward again. "You should have asked a teacher or prefect for help; you didn't. You should have handled the troll without killing it; you didn't. And you certainly shouldn't have addressed the teachers disrespectfully, attempted to conceal weapons from us, ran out when you knew I was likely to discipline you, and insulted me while you did so—but you did. I was not the one throwing a tantrum in that room, Potter."