Why Do People Act Shocked at 50?

Why do people have that disgusted look on their faces like they are shocked and appalled at the sex scenes in "50 Shades of Grey?"  Come on now, if you didn't think you were going to see sex in this movie, you are delusional. What did you think the movie was about? Grey cats? Old people? Coloring? Painting? If you read the book or even a few pages of the book you knew what it was about. If you didn't read the book, you surely saw previews for the movie. Did you go to the movie just so you could act disgusted? My advise is that if it bothered you, don't see the other two.