realism. the characters have to be believable.
action. without action, i think every book/movie is a failure. fighting scenes are always good, but more than one major fighting scene totally destroys the piece. add suspense. without it, a book/movie would be too predictable and that's never good.
mystery. you have to be wondering what's going to happen next. there has to be an unsolved question throughout the whole piece until it reaches the end, but if the question is not resolved, then it crashes the whole idea.
emotions. there cant just be one emotion, you need all of them.
plot. the plot has to be unbelievable. it cannot be generic and it must have lots of twists and turns.