7. Convincing yourself that it must be good because it is generally said to be, even if you don't like it.
6. Getting so hung up on who-done-it that you miss the great description along the way.
5. Getting suddenly squeamish about being entertained by murder and violence.
4. Evaluating the writer and the book rather than enjoying it.
3. Assuming the "bad guy" did it.
2. Paying too much attention to how an author operates the machinery of a mystery.
1. Jumping ahead to the end before you've finished reading it.