When I worked at the Restaurant DuBarry in Boston, my bombastic boss provided specific instructions on using a large kitchen (a.k.a., chef’s) knife. “Idiot!” he screamed (his pet name for me). “This knife she is not a guillotine! You roll ze blade like zees.” In the about.com video above, the chef presses down on the blade. OK, he rolls it a bit. But not really. Far worse, his fingertips are not facing straight down. That’s an excellent way to remove flesh and commence leaking. (Click here to see the proper technique.) And what up with the chef’s index finger jumping across the blade to stabilize the finished zucchini slices? Better to tilt the blade after the cut to push the finished slices out of the way. Remember: safety first, accuracy next, speed last. If at all.