I think I've learned to perfect the, "what do you MEAN you're not going to do the thing I've asked you to do?" look/attitude.
The, "of course you'll do it" look.
The, "there's no other option" look.
The, "I'm amazed you'd even think to ask such a question" look.
The, "don't be silly" look.
I got to use it Monday when I prepped my AP Calculus kids on the fact that they had homework that was due Tuesday even though I wouldn't see them due to the state test, and they'd better walk their butts over to school from whatever vacation they think they're getting and hand in the no-lates-accepted AP-exam--multiple-choice corrections to me.
Of course I'm semi-bluffing and know I'm asking a lot of them, but I think the "look" gets them to get off their duffs, and maybe I'll have a higher turning-in rate because of "the look". I also reminded them of the fact that the AP exam is coming up next week, and don't give up now, and you can do it, and it would be a shame to work so hard all year and flake out now and miss the opportunity to pass, and rah-rah-rah ...
Plus I get to practice being a bad-a** when I think I'm a softy inside ... but maybe I'm fooling myself, and I've become mean and cranky with high expectations. Oh well, they usually rise to the challenge - and I guess it's our job to push them to do their best, even though it's their job to resist and try to get away with what they can. Our little teaching tug-o-war.