I don't remember the exact book but it was something for a class I took about the Greek origins of Christian thought. I think it had something to do with the Nestorian controversy. All I know is that is was about 200 pages and I read the whole thing cover to cover (I wasn't understanding anything with skimming) but retained/understood NOTHING! What is the Nestorian controversy in the first place? No clue.
Also, Sylvie and Bruno by Lewis Caroll. I tried to read it in high school and thought it made no sense. Maybe I'll try to revisit it someday?
Also I just wanted to share a tip for reading stream of conciousness that I found helpful: as you are reading, don't try to understand/analyze anything or create a coherent sequence of events. Just take it in as it is and sit with it. Then, at the end you can try to draw some conclusions, make some connections and/or note things that stood out to you. Honestly, I think life is a lot like that too.