Reasons for reading five or more of an author's books (with statistics! and lists!)

Nowadays, I never consciously read deep into a writers' ouevre. I'm almost always ready to content myself with his or her 1-3 most critically acclaimed works. For instance, I really loved Vanity Fair, but I've never even been tempted to read Pendennis or Henry Esmond or any of Thackeray's other novels. I figure that there's a reason that you never hear …