|The difference between a poor systems designer and a good one. And since you can't architect a system without knowing the business, it's also the difference between a good analyst and a poor one. And in order to come up with a feasible solution, you also need to be technically competent. And in order to properly communicate your thoughts, you also need to be able to write and talk coherently.
Not something one just learns from books; you have to have lived it; and probably have at least one system under your belt to qualify.
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food