Do you need to have a twist in a book (or several for that matter), what I’ll call the ‘Boo!’ moment?
I was talking to ‘S’ a couple of weeks ago, she’s the only person in the office who knows I write and has a copy of the books. She’s read the first one (which she enjoyed) and she’s just finished the second. We were discussing what she thought and I asked her about a particular event. Good she said, but she saw it coming.
Obviously I can’t go into too much detail, but the event in question fundamentally changes the relationships in the book. From the way I’d written it, James (Sam’s brother) was becoming more disturbed and nasty because of something that happens at the beginning of book two. This escalates, but he’s manipulated into making a bad choice and to me writing how he was manipulated was one of the most interesting and rewarding parts (and I know it worked as one of the test readers said I was ‘evil’). I think the people who read it could see what was coming and I made no attempt to hide it, after all if I did and he suddenly changed people wouldn’t buy into it – out of character etc.
My wife even said she felt sorry for James which I guess is a compliment, after all if she didn’t have any attachment to the character she’d have just shrugged and carried on.
I guess the question is, which would you prefer – a book that goes ‘Boo!’ every 100 pages, or one where the twists are a little more open but build up and make you think ‘Oh, No’ ? At the end of the day that’s personal choice I suppose and both are valid. Some books work better with a big reveal at the end (or middle or whatever) and it’s relatively easy to conceal them, but when you’re talking about the way a person changes over a period of time it’s more difficult to keep the ‘Boo!’ a surprise.
Oh and just to clarify, it was my wife that called me evil.
W.Chaser 
Fantastic question.
I’m an opportunist with my writing. I only put in what I think is necessary. When the opportunity arises, I use it and adapt my style or mechanisms to the story as necessary.
Some things are necessary for the reader to see coming. It builds tension if done right. The degradation of a character’s morals, for example. If the character was likable to begin with and had the reader endeared to them, then the horribles acts they commit later will be a wonderfully evil rise of literary stress in the reader’s mind. Equally as breathtaking is when a good character trusts another person who makes the same transformation. It provides a type of irony. These don’t need the BOO moments as much as they need simple consequences that live up to the build.
At other times, though, a surprise or a twist is necessary and I think if it can be done and makes sense with the story, then it should. I’m a mechanism heavy writer. I want my works to be equated to roller-coasters. I love tension and surprise and destruction and character flips, everything that puts the reader as far into the book as possible as quickly as can be achieved.
So, I’m saying I agree with you on all counts. The story is what dictates the methods used to convey it.
I have always been a fan of books that let a story unfold in an unhurried fashion. Books that hit me with something one page after the next are simply exhausting. I like time to think and consider the characters, so when something big does happen the impact is more greatly felt.