[Honestly, the smile is probably more menacing than all of her threats combined; he's way too used to assholes who stomp all over him with the most pleasant of faces, after all, and it makes his eyes narrow and his teeth bare like the dog he is -- for a split second. A split second of almost-confrontation. He technically has the upper hand here (to him, anyway).

Like hell he'd let insults like those go unchallenged, after all.]

Hmph, you throw around idiot, idiot, weak like you know everything, but you know nothing about me, stupid hag! [Two can play at ageism!!!] I don't know what hole you crawled out of, but you'd better--