Do you finish all the books you start?

I've been learning lately that I don't have to finish every book I start. I have thousands of books I would like to read and I'm not wasting time on one I don't enjoy or I find inappropriate.

I stopped reading Gone Girl at page 60. It wasn't that the book was bad, I threw it out for the language. I'm trying to teach my children to read good books and I didn't want to set a bad example. 

Do you finish every book you start?
What makes you stop reading?
Did you enjoy Gone Girl?