Which two measures are often at odds when you are trying to evaluate whether a book is good or not?

The question is very personal.For some people there are certain measures that make a book godd and for others the measures are completely different.For me the two measures at odds are whether the story is narrated in a way the reader gets so involved that the book is unputdownable and the other is the characters.If I get trapped by a story in which the development and unpredictability of the characters make me continue reading , the book is good for me.

a. the scene is structured as a dialogue between two characters in their own informal language.

there is no excerpt.

put the excerpt in the comments and ill answer.