when i was an hourly i'd say something along the lines of "you wish"
as a PT supe, all of my people follow my directions pretty well, thus avoiding such confrontation entirely
then again, i never ask anything of my people that i couldn't do myself, and if they can't handle the work i give them, i hand them off to someone else; i have too much work and not enough time to drum people out of UPS and i won't train and lead someone just to harass them about production metrics handed down from someone i've never even met
i'll leave the firing/harassment to someone who enjoys that nonsense