Is Moby-Dick really a tougher read than Fifty Shades of Grey? Noah Berlatsky argues that the distinction depends on the reader:
…”difficulty” seems to hold out the possibility of more objective standards—to assure us that these books, over here, by Joyce and Faulkner, are 1000 pounds of pure prose, while these books over there, by Stephenie Meyer or Tom Clancy, are sniveling 90-pound weaklings of meretriciousness. It’s as though “good” may be relative, but “tough” is always and everywhere the same.