I will start:

Blood Meridian: People often quote it as the most disturbing book they've ever read, but for me it was plain boring from start to end and had to force my way through it. Maybe it's because I'm not American, but could not relate to the scenery.

The Hitchhiker's Guide to the Galaxy: I couldn't find it funny and after about 50-60 pages I abandoned it. Not my kind of humour I guess.

The Curious Incident of the Dog in the Night-Time: Read it in one day, but for me it was a complete waste of time. Didn't like it one bit.

Lord of the Rings: Just don't like the genre, but it's my fault. Did not like the movies, nor Game of Thrones. Everything too 'fantasy' is not my genre, but I'm not criticizing the book. If you're into the genre I guess that Lotr is a must-read!

On the other hand, books that I did like were: 'Gödel, Escher, Bach','House of leaves' (although it felt empty. Beautiful experiments with the format, but lack of actual content. He could have done better IMHO), 'Kafka on the shore', and I plan on reading some more (Infinite Jest and Gravity Rainbow, which I tackled a few times, but stopped after about 150 pages. I have to try again).

What about you? What books that you always see recommended did not like?