My nemesis: The Onion.
If you are going to cut yourself with a newly sharpened knife, it will most likely be when dicing an onion. They are slippery, evil creatures of the night who laugh at you as you cry helplessly while trying in vain to dice even tasty morsels of oniony goodness.
Cry no more, my fellow chefs! Presenting, Gordon Ramsey's How to Chop an Onion: