First of all, let me say that among books I've laid aside have also been renowned classics and award-winning contemporary novels. Sometimes I might recognize stylistic skill, but the content of the book may still not be to my liking. The opposite is also true: If I find the story or characters or facts or ideas interesting enough, I might overlook certain deficiencies in language and narrative style.
That said, I would say that good writing includes the ability to capture the reader's interest from the start and keep it up until the end. Really good writing also leaves behind a sense that I might want to read the book again some day, even though I know how it ends. Or write down quotes from it, or recommend it to others, or discuss it.
Bad writing, consequently, would be the kind that never manages to get me engaged in the story or the characters at all. Bad writing also often includes things like needless repetition, too much predictability, sidetracks that take you too far away from the main story, introduction of things that are never properly explained, or last-minute "out of the blue" solutions at the end.