I used to feel obligated to finish all the books I started reading. That, of course, was before law school. Now, if I don't want to read something, I just don't. I have enough stuff I dread reading for school!
I think that there are tons of good books out there, and tons that I have not read yet. I am on summer break right now, until August 22, and I have a whole Kindle full of cool books to read before I go back. It's like I crave reading something other than legal stuff when I'm not in school, but I can also read fun books while I am in school now that I'm a 3L. Trust me, I read everything I'm supposed to for class. I'm terribly frightened of being called on and being unprepared. But, I sure enjoy reading delightful books as well.
The last book I gave up on was The Bees of St. John by Rachel Coles. Nothing against her or the book, but once it started talking about alien life forces, I was a goner. I hate science fiction reading, and I had no desire to finish it then. I don't have anything against science fiction – I love Star Wars, Star Trek, etc., but I hate reading about it. It's just too weird. So, I ditched that book most recently.