I find that seeing the movie before reading the book usually works better for me. Once I see the movie, I can usually separate my memories of the movie from the book. However, if I read the book firs, I think about the things that get left out of the movie.
I used to say that I am not to concerned about getting hit by a car, after all with my size I would do more damage to the car than it would do to me.
I used to say that until I got hit by a Mercedes. No I did not receive a big pay out, because I was J walking at the time and I did not want to receive a ticket like friend of mine did, so I told the driver that I was unhurt and kept going. The good news is that I was mostly unhurt. I was able to jump before impact and push off of the hood of the car.
One of the big ones for me is The Dirty Dozen. The movie is about 50 pages of a 500-page book; and even then, they changed some of the characters.