Ah, the power of sauce. A sauce finishes the meal. It is an intimate partner, a yin to a yang so to speak. There aren't many main dishes that don't benefit from a sauce except maybe a perfectly cooked filet mignon or strip steak. Very rarely will you go into a restaurant and get a plain piece of chicken, veal or fish.
Restaurants take pride in their sauces.
Creating a succulent new sauce is a source of pride for a chef. They can't wait to share it with everyone. The word sauce is derived from the Latin, salsus , meaning salty. Roman sauces were distinctly salty as a necessity. Their role was not only to flavor the dish but to also mask the unpleasant taste of ingredients passed their time.