Fulfillment

The goal of a writer is to leave the reader with a sense of fulfillment. How do you define fulfillment? It's the feeling you have when you have just finished eating a delicious meal.
Delicious. That's it, isn't it? You hope your readers find your work delicious.
Fulfillment, then, is a literary principle that defies math because the whole is equal to more than the sum of its parts.
A meal isn't delicious because it's made up of meat and potatoes and vegetables and a beverage and dessert. It's more than the sum of its parts.
A story isn't fulfilling because it's made up of words and sentences and paragraphs and commas, periods and question marks. It's more than the sum of its parts.
And when that "more" turns out to be just enough, the reader enjoys fulfillment.