I was thinking this as I sorted out dd's bookshelf with her at the weekend. We threw out Moonfleet, Children of the New Forest, and The Far Distant Oxus. All three were mine, and despite starting them lots of times (I always thought I ought to like them, they sounded so promising) I never got past the first few chapters. DD has also never read any of them.
It made me wonder if other people have books like that; ones they always wanted to like, but never quite could? (Also prompted by the fact that The Children of the New Forest is quite often recommended on here, obviously other people didn't have the same problem with it!)