I think different readers enjoy different things in a book. Reasons for why a person may like a book may vary from individual to individual. For me, the most important reason for liking a book would depend on how real the characters feel to me and how much emotionally involved I feel with the characters. If a book fails to make me care for the characters, I lose interest. It's even better if the book has philosophical undertones. Additionally, prose also matters. So, I can't give an opinion on what makes a good book; I can only speak for what I like. And if I fail to get interested in a book beyond ~25-30% mark, I DNF because life is short and I would rather read for pleasure. For me world-building is not important, however someone who loves world-building over everything else might love a book which someone like me may not like at all. So books of different styles are great for different people who would enjoy them.