Finishing the book

Amazon had told me id like this book. I requested it from the library and started reading it last week. For the first 30 pages or so I was with the author, but it started getting a little over the top for my taste. I stuck with it for another chapter. But then I put it down on the counter where it sat for days. I debated picking it up a few times but never did.
I ended up just returning it to the library unfinished because it is a very popular book so there are other people waiting to read it. How do you feel about finishing a book that you aren’t really in too?  When do you give up?  Do you ever feel a little bit guilty after giving up?