For many people overplanning things like which books to read that are usually spontaneous and unplanned is an example of trying to control more aspects of life than is desirable. We need to be free and unfettered in many parts of our lives. There is endless variation possible. For instance if a book is not fun for you, you may persist in reading it all if that fulfills a specific goal for you, or abandon it, or skip to the end etc. depending on the circumstance. Having a list of books to read and having books in front of you you plan to read are both good things, but from that point on anything that happens is fine. Serendipity plays a very positive role in life and trying too hard to organize things that are by nature somewhat disorganized does not enhance the marvelous accidental discoveries of serendipity.