Back when I used to teach writing courses, I railed against the temptation of using fictional or hypothetical examples, because they short-circuit your thinking. After all, how do you create a hypothetical example? You do it by projecting out onto reality what is already in your head. That's a great way to reinforce your existing preconceptions, but it's a lousy way to learn anything new. Real-life examples reverse the process. Instead of projecting your existing knowledge out into the world, they help you to move in the opposite direction, projecting facts from the world back into your head. Real examples carry with them a whole factual context, which can't just be bludgeoned into a pre-constructed narrative.

-Robert Tracinski