I'll be the first to admit it: I'm a fan of popular fiction. I desire enjoyment from certain factors of pacing and style that the literary elite consider "common" and I, in turn, generally find "literature" to be incredibly pretentious. This has led me to hold what some might consider "uncultured" opinions about various great works.
Which brings us to Don Quixote, which many in the literary elite consider to be the greatest novel ever written.
Did I love Don Quixote? I wouldn't go that far. Does it deserve to be called the greatest novel ever written? I'm willing to put it on the short list.
Here's the thing: Cervantes published Don Quixote in the early 17th century, while Shakespeare was still working through his "tragic" phase (Hamlet & whatnot). By rights, it should be like so much other "classic literature:" dense, slow, utterly irrelevant to modern life, and soporific. Instead, it's dense, slow, engaging, and surprisingly relevant. Cervantes manages, almost continuously, to be clever in ways that transcend the 400-year gap and resonate with us now. There's no question that adapting to the writing style of that era is a challenge, and Don Quixote will be slow going to readers accustomed to modern pop fiction. But most intelligent readers will consider this a price worth paying.
Why Don Quixote still works stems largely from its having taken the formulas of "heroic knighthood" (which we are still vaguely familiar with as legend today) and showing it to be cartoonish and absurd. Despite the cultural gap, modern readers will still get the gist of the parody, even if they haven't read the chivalric literature that it is an explicit parody of.
The other reason the story works is because, strangely, we find ourselves continuously at odds with the author over the character of Don Quixote himself. We are told, at every turn, that Quixote is a fool, a madman, and a sinner. Cervantes breaks from the traditional role of a passive narrator to make constant judgment on Quixote's failures and flaws. And because we see Quixote so maligned by both his own author and everyone in the book, we as the reader fall in love with him. By writing a book about a dreamer with unassailable ideals but using the narrative voice of a vitriolic cynic, Cervantes forces us to stand up for the nobility and purity that Quixote achieves. Cervantes has, in effect, martyred his own protagonist in such a dramatic way that it falls to the reader to elevate Quixote to the status of saint.
And any book that can pull that off is worth the difficult prose.