Really depends on the book, especially the earlier stuff is slightly more difficult to get into. His language and style and historical references really tickles my brain, but what people usually love about him is the absolute humanity and very sharp observations about people and things, and some of the most hardcore philosophies gently wrapped into a nice puffy coat of humour.
One of my favourite quotes:
"Death: What would have happened if you hadn't saved him?
Susan: Yes.
Death: The sun would not have risen.
Susan: Then what would have happened?
Death: A mere ball of flaming gas would have illuminated the world.
Susan: Alright, I'm not stupid. You're saying that humans need fantasies to make life bearable?
Death: No. Humans need fantasy to be human. To be the place where the falling angel meets the rising ape.
Susan: With tooth fairies? Hogfathers?
Death: Yes. As practice, you have to start out learning to believe the little lies.
Susan: So we can believe the big ones?
Death: Yes. Justice, mercy, duty, that sort of thing.
Susan: Well, they're not the same at all.
Death: You think so? Then take the universe and grind it down to the finest powder, and sieve it through the finest sieve, and then show me one atom of justice, one molecule of mercy. And yet, you try to act as if there is some ideal order in the world. As if there is some... some rightness in the universe by which it may be judged.
Susan: But people have got to believe that, or what's the point?
Death: My point exactly. You need to believe in things that aren't true. How else can they become?"
