If you’re not enjoying a book, will you stop mid-way? Or do you push through to the end? What makes you decide to stop?
It depends on the book. If I’ve made it halfway, I’ll often figure I’m interested enough to come this far and I may as well keep on going. Or if the book has multiple plot threads, I may skim the ones that don’t interest me and pay closer attention to the ones that do.
And then there are the times I “cheat” and if the book isn’t doing it for me but I’m curious to see how it ends, I’ll look it up on Wikipedia or skim reviews on the various book social networking sites.