BIG SURPRISES and book signing

I have read a couple of novels lately where the author seemed so busy surprising me with some incredibly devious plot turn that everything else became unimportant. The characters began acting stiffly, their dialog stilted because they had to say what the author had planned to lead up to the BIG SURPRISE. I'm all for big surprises. I have plenty of them in my novels. I have even written novels with only the plan of a big surprise at the end. But that's not the only thing that readers want...