Basic Knife Skills

Allumette

Every cooking school I've read about and every chef I've seen talk about essential skills of a chef starts with knife skills.  This is an interesting topic to me because it seems obvious at first, but if you consider the whys of this starting point you see how there is much more to it than simply knowing how to chop vegetables.

Allumette -> Small Dice

Of course, making even equal cuts serves two purposes.  First, it allows for even cooking so your food reaches temperature and texture at the same time.  It is a disaster if some of your potatoes are done cooking while other, larger, pieces still have a ways to go.  Second, a good cut is pleasing to the eye, while uneven cuts make a plate look sloppy.  This doesn't mean all cuts need to be platonic, but it does mean that your pieces should be isometric.

Julienne

There is another reason, one that I think is no less important, although it is a subtle point.  Learning to making even cuts trains you to be laser focused on details.  It seems to me that this in particular has profound implications for the rest of your cooking beyond the mechanics of heat application or the aesthetic qualities of your dish.  The attention to detail separates good from great.  The finesse you pick up separates great from legendary.

Julienne -> Brunoise

I think knife skills also send a signal, to superiors and your guests, that you take your craft seriously. Also, it signals that what they are about to eat was prepared with care, and is likely to be good.  Sloppy cuts signal that you're too busy or careless to craft the dish--that what they are getting isn't your best effort.

Batonnet