I work in a kitchen and today's chef surprised me when he said that “different people do things differently.” He meant that he was not astrict to doing a quiche the way the previous chef did. I think chefs being whimsical is fine otherwise we would get sick of always eating the same food.
What went through my mind, though, was that the customer would not get the usual stuff made in the usual, predictable way. This may be more important than it may seem at first sight: when you go to McDonalds and ask for a Big Mac what you get, whether you are in Australia, in America or in Europe, is a predictable, standardised, fine-tunned burger for a set price. You went there for that stuff, you got it exactly as you wanted and you paid the price you were prepared to pay. You are a satisfied customer and McDonalds is your restaurant.
There are in fact many benefits to reap from standardising kitchen food products. Apart from the ones mentioned above, standardisation allows for control of quantity and quality of inputs into the foodstuff; it allows the food taste to be developed to an expected kind; it allows control over other inputs such as energy and labour and makes budgeting more effective.
As a matter of fact, standardisation of foodstuffs was the key to the development of the McDonalds phenomenon with its predictability of product type and quality, mass production and strict control over all economic inputs.
If instead you went to your favourite burger shop and ordered the usual, how would you react if your chef included carrot together with your tomato, lettuce and onion in your burger? He could possibly say, as if coming out of The Muppets show: “yoo-dou-be-doo, here is your burger, sir, today with carrot.” “What?”, you would exclaim with understanding surprise: “I don't like carrot and especially not in my burger.” “Dou-be-doo, but you like carrot, yes sir, because today is carrot day for me.”