I think that sense of surprise, that you don't know where something is going, or what's going to happen, even as you write, that you're making it up as you go along - that's important to me. It's not a question of shock or surprise in a gimmicky way. It's that as you read, you become more deeply into something and into what happens, and become more involved and engaged, you're learning something or you're appreciating something or seeing something differently - that's what's surprising.