It wasn't until a decade after college that I picked up another Steinbeck novel. and after finishing Cannery Row, the only question i could ask myself was, WTF were my teachers thinking assigning Grapes of Wrath vs some of his much shorter, less complex works that could be read in a couple days. The whole book is shorter than the section of Grapes that most people describe as being the slog you have to get through to enjoy the rest of the novel.
I read a lot, and I can say with a fair bit of confidence the one long lasting result of assigning these books in HS is to guarantee most people have a life long repulsion for long "classics".