I'd say intelligence has little to do with it. I, for example, love the book, and I'm not the brightest bulb on the tree. On my first attempt I made it to page 6 and threw it down, certain that it had nothing to offer me. I tried it again a few years later and it blew me away. Sometimes its just your mood or your concentration: sometimes I don't want to work quite so hard in my reading. I sometimes return to a book I really loved and find little reason for it. Sartre's Nausea impressed me greatly in my younger days. When I went back to it, it was just a guy looking at his beer and feeling sick. Probably time to go home, I'd say. Each to their own. But I'm glad to hear from so many kindred spirits, and several who plan to re-read... or dare I say, re-Joyce.