It was probably a combination of (a) being forced to read it in the summer, (b) the heavy handed allegory, and (c) just not being emotionally ready for that kind of literature. I just remember how the English teacher was making such a huge deal out of the fact that the doctor was constantly described as fat to draw a connection to greed, and in my head I remember thinking that characterization seems mean to fat people. I think I liked Old Man and the Sea, or at least it was impactful enough that I would dwell on parts of it after the fact.
But I was uninterested in English/Lit as a kid, I remember when we started reading To Kill a Mockingbird in 10th grade and that as an adult I'd definitely categorize as super important literature but I just remember the first chapter or prologue being about the mystery of the Boo Radley House and being intrigued about that like haunted house setup, then feeling like there was a huge bait and switch where the book immediately sidetracked into "grownup things" and didn't circle back to the fun mystery until the end. Maybe I was a textbook case as to why English class was important, I had zero intellectual curiosity.