 You're dealing with ingredients that are different. I like to say, for example, an artist will squeeze a tube of paint and know exactly what color and exactly what the texture and consistency is of the paint. Every day, a chef will show up at their restaurant and new ingredients will be delivered. There are so many invisible forces coming down on those ingredients. It's impossible to know what your toolkit is going to be every day, even if it is the same ingredient. From day to day, a tomato can be different.