Fight Club. It wasn’t fun to read it felt like the author was ploying with me trying purposefully to confuse me to a point where it forced me to become disinterested. However with the movie i was captivated every second. The book’s attempt to obscure and mystify the reader might have been an intentional stylistic choice, but for me, it didn’t translate well.
The baseline here is Jaws. Peter Benchley’s book was sub par, but Spielberg made a top notch film out of it.