Not all people are chefs, but we are all eaters.  Most of us need to learn how to follow a recipe at some point in our lives.  To create dishes with good flavor, consistency, and texture, the various ingredients must have a relationship to one another.  For instance, to make cookies that both look and taste like cookies, you need to make sure you use the right amount of each ingredient.  Add too much flour and your cookies will be solid as rocks.  Add too much salt and they'll taste terrible!