Just now, I heard a song that I've heard hundreds, maybe even thousands of times. And for the first time I understood that a word I've always heard as "pain" is almost certainly "paying."
Either word works in the context of the song, and we've long been accustomed to not catching mumbled or slurred lyrics, or not understanding them even if we do (such as the neologism "pompitous" in Steve Miller's "The Joker," or the entire song "Whiter Shade of Pale"). But it still makes me marvel whenever I discover something new in something old, when I finally get a reference that always floated over my head before, or when I see the familiar in a whole new light.
One reason I like to reread is that I like to see how works change as I understand them better, and as I grow and change myself. Some works lose their luster over time; others gain. Nothing is static, even when the words themselves don't change. Society changes; we change; our tastes change. One work of art can bring multiple experiences.