Have You Ever Hated A Book, Then Come Back To It Later And Loved It?

LibraryThing's science fiction group had a great discussion about "wrong book, wrong time" situations, where you hate a book, but much later, you rediscover it and fall in love. What books are you glad you gave a second chance to?

Not surprisingly, a lot of the books people are listing in that thread are ones that might not work as well for younger readers, like J.G. Ballard's works, Ursula Le Guin's The Left Hand Of Darkness, and A Canticle For Leibowitz. (The last of those, incidentally, was assigned in school, thus proving that any book immediately becomes horrendous when it's a school assignment, whether it's a 200-year-old literary tome or a science fiction classic.) But there's also Dune, which just didn't work for someone the first time out, and the works of Harry Harrison and Harlan Ellison. (The thread degenerates a bit into bashing Ellison and Asimov, towards the end. Fair warning.)

Which books have you tried and failed to appreciate, then come back to and discovered a new appreciation for later? [Library Thing]