There should be surprises in books then. Characters should be capable of surprising us yet at one and the same time there should be clues within the story that the character is actually up to the task.
What you want to achieve is the reader being able to look back and realise the clues were there. I love trying to guess at the outcome of the story as I read it and sometimes I get it right, sometimes I don't but the important thing is I am engaged with that tale. The writer has done their work well and is keeping me reading that story until I get to the end and find out what did happen.