I finished it almost all the time, but I wish I were better to quit on bad books/movies, because its frustrating to waste time on them. But at the same time I hope they get better or have a surprising ending, which could make up for a bad start. Only book I remember I've stopped reading was Terry Brooks "The sword of Shannare" when I realized how close it was to LotR. When it comes to movies I have tried to have a 20 minutes rule, where I after 20 minutes decide, if I want to finish it or not, if it has a bad start. But I almost always end up watching them to the end. What do you do?