The other day, I reached for my favourite knife: a 23cm Japanese carbon stainless-steel santoku blade that I keep super sharp. To my horror, I found the knife blade-side down in the drying rack and, upon examination, that the delicate pointed tip had been nicked off.
I showed the damage to the person responsible. I had scolded her before for air-drying the knife in this way and warned her that if it happened again, she wouldn't be allowed to use it.
Knives should be treated with respect - and not just because they can inflict serious damage if handled carelessly. Without a knife, you can't cut; without a sharp knife, you can't cut well. A dull blade tears away at food, while a sharp one cuts effortlessly and cleanly so that the minimum amount of liquid is released. To test this theory, try slicing a ripe tomato with a dull knife, then contrast the squashed, pulpy result with the neat, tidy pieces you get when using a sharp one.
Each part of the knife has its uses: the pointed tip (of santoku and chef's knives) is good for delicate slicing, while the rest of the sharp end of the blade is better for more standard chopping and mincing. The flat side of the blade can be used to crush ingredients - it's perfect for bruising garlic cloves, so the skin is easier to remove - and the back of the blade can be used to tenderise meat.
All-purpose knives, such as the santoku, chef's knives and cleavers (the smaller-bladed ones, not the heavier type used for cutting through chicken bones) have their advantages. At culinary school, I was trained to use a chef's knife and it was considered wimpy to use anything less than a 25cm blade. Students learned to use an energy-efficient back-and-forth rocking motion to chop ingredients.
I've since given up the chef's knife and switched to two others: the santoku, my everyday knife, and a smallish (the blade is about 16cm by 8cm), extremely sharp carbon-steel cleaver. The santoku has a modified blade - rather than being straight, as is traditional, it's slightly curved so I can employ the same back-and-forth motion I'd use with a chef's knife, but it's just as easy to do the up-and-down slicing used with other santoku knives. The straight blade of the cleaver means it can be used only in an up-and-down motion, but its sharpness and heavy weight makes it great for hand-mincing meat.