The Stranger, but it definitely did not help that I read it in French and was still learning. Even then though, I feel like even once I understood what was being said I didn’t really understand what it was trying to do, and just thought it was weird.
Books
Tale of Two Cities. Dickens’ descriptions are long but they stack. The next time he describes the same place he builds on his previous metaphors. It reminds me a lot of “Hamilton” where Lin Manuel Miranda will have 3 different meanings in a phrase.
Lin Manuel is the new Dickens.
Norwegian Wood by Haruki Murakami. Read it when I was 14 and didn't fully grasp what the characters were going through, I especially disliked Midori and thought she was outright annoying. Until I re-read it as a young adult, it suddenly hit me that she felt insecure beneath the outspoken and rebellious appearance. I read the book a few more times in my adulthood and every time still brings me new perspectives.
I read Tropic of Cancer too young, lol. It was shocking. It is still shocking, but it was shocking too.