Quality of Reading

After reading interviews with Zadie Smith and essays by her, and being impressed with how sharp and interesting she is, I finally -- finally -- got around to reading On Beauty. I liked it very much; this novel has sophistication and depth. It is the story of two black families -- one mostly American and one British; one liberal, one mostly conservative -- who intersect at a small liberal arts college near Boston. The book takes on the culture wars, black identity, class issues, love and fidelity, and, of course, beauty.
Playing alongside the novel for me, though, has been Smith's essay on the importance of reading. Her analogy of a violinist playing a composer's work haunts me, because I play the violin, and I know there are diligent ways to practice and sloppy ways to practice. It makes me wonder, am I reading sloppily? Am I doing justice to the work I'm reading?
I've often thought that I sometimes read books too fast to really enjoy and even digest them. Books that I find to be clearly and simply written are books that I read fast -- books like Harry Potter and authors like John Grisham and Anne Rice. With Harry Potter, I've noticed myself reading about half of each sentence, getting the gist of where it's going, and skipping to the next sentence. (I suspect that's what most speed readers do.) But even books that are written with a more complex style, sometimes I tear through those, too. So lately I've been trying to consciously slow down, to read a little slower, to savor the language more.
But what else do I do that's bad? How about stopping in the middle of the chapter, or even worse, in mid-sentence? I certainly do that sometimes. Isn't that doing harm to the reading of the work to stop at an unnatural stopping point?
So I've been trying to be more respectful in my reading -- not reading right before bed when I'm exhausted, or when I don't have enough time to finish a chapter. It's definitely slowing me down. But hopefully it's making me a better reader, too.