DNF'ing Books

This is something that's been on my mind a lot lately. I'll admit, I don't go into every book expecting to like it. I've read books because everyone else is talking about it and, although I'm not expecting to like it, I read it anyway. (Hello, Clockwork Angel - but that's another subject entirely.) Most of the time, I want to like the book.

I want every book I read to be fun and enjoyable and leaving me looking forward to the next in the series/by the author. Sadly, that can't always happen. Beyond that, sometimes a book sets so badly with me that I have to DNF (did not finish) to save my sanity.

Just last month I DNF a book after reading over 150 pages. The book hadn't been speaking to me at all and by that point I was bored and just said enough was enough. (Reading some of the reviews made me think I made the right decision.) As I'm writing this (earlier in June) I just started a book. Awesome hook. A little gritty for my tastes but things were set to be interesting - then I reached page nine and was left feeling sick. In the first thirteen pages, there have been no less than three moments that I would have been much happier without. (Decomposing corpse with no legs in the alleyway; 'we're eating this adorable puppy for dinner'; skeletons attached to the airship clock.)

The truth is, I hate not finishing a book. It's for this reason that I've never been a fan of watching movies that are aired on TV. When I start something, I feel this compulsion to finish it. Even if I'm not actually enjoying it. I need to know how it ends. But sometimes there's just something in the book that makes me step back and go 'I quit'. (Like EATING A PUPPY!)

How about you? Do you finish every book you start? Do you have a hard time DNF a book? If it hasn't gripped you by the first chapter, do you have no problems putting it down? Do you limit yourself? Like if you've made it past the half-way point, you have to finish it? (I used to be like that.)