What makes you stop reading a book?

I’ve read Harry Potter and you, sir, are no Harry Potter.

That, essentially, is what many readers were thinking when they dug into “The Casual Vacancy,” the first adult book by Potter author J.K. Rowling. It’s one of the five most-abandoned books on Goodreads.

Goodreads has parsed its data and polled its users to discover what makes readers give up on a book, and, conveniently, created an infographic that presents the results.

There’s something a little schaudenfraude about an unfinished book, a little slowing-down-to-see-what-happened-at-the-car-accident. Why would someone who likes reading -- Goodreads users are people who find reading to be good fun -- set a book aside? What horrors might it contain?

Maybe handcuffs. Another of the books most likely to be left unfinished, E.L. James’ erotic romance “Fifty Shades of Grey,” was a bestseller that didn’t turn everyone on. “I am embarrassed for all of us,” one reader commented.

But while embarassment is bad, tedium is even worse. The biggest reason Goodreads readers put books aside was because they found them boring -- an overwhelming 46% wouldn’t stick with a book that was too slow. The nearest other reason for abandonment was poor writing, cited by 19% of responders. Other replies were all less than 10% each -- poor plots, unlikable main characters, “extremely stupid” and the like.

While bestsellers top the most-unread list, classics didn’t escape the cold shoulder. Goodreads’ five most-unfinished classics include two of Western literature’s most essential books: “Moby-Dick” by Herman Melville and James Joyce’s “Ulysses.” Perhaps they’re not abandoned but set aside for a later, longer day.

Thirty-eight percent of respondents never leave a book unfinished. About 18% stick with a book for 100 pages or more; more than 43% bail out before reaching Page 100. “I once heard the rule for when to abandon a book is 100 minus your age,” one reader commented.

That brings home something we’d rather not think about: There are so many books to read and only a limited amount of time in which to read them. Is there something noble about sticking with a book to the end? Or is that just foolish if a book isn’t at all interesting?

Of course, all of these things are in the eye of the reader. One person’s poor writing is another person’s page-turner; one person’s must-read classic is, for another, impossibly slow. What makes you give up on a book?

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