The floorboard!
Any sharp tool used to cut, shave, chop, or shape should be handled with extreme care. This includes the kitchen knives you use on a daily basis. Even professional chefs can slice their hands open with a sharp knife, despite being in the business for decades.
Apart from a dull blade, one of the most common causes of knife-related is leaving it hanging over the edge of a kitchen countertop. The slightest nudge will cause it to come falling blade-first into the ground and possibly crudely amputating your pinky toe. We know this is the last thing on anyone’s mind, but that’s going to leave a permanent mark on the hardwood floorboard.