Within the confines of the movie, and the world it created….Yes, thats the entire point of a horror movie. There is a large segment of people who just shouldn't watch horror movie, because they are looking for a feeling that doesn't exist. A real horror fan understands that immersing yourself in the story and the conceit of the movie it part of it. So, yes I jumped a few times, and was unnerved at some of the images, and implications….because I put myself in the characters shoes and world. And, funny as it is, I saw it late night, and there was maybe 3 people in the theater, including one dude sitting in the far back of the theater. As the credits rolled, and I got up to leave, I won't lie and say I didn't look back, like was he really there….it's all part of the fun….
Now, was I scared like real life or death? No. Of course not. I am not accusing you of this, but people who constantly say horror movies don't scare them are just not worthy of argument or discussion. Granted, BAD horror movies are unable to convincingly pull you into their world, and for a variety of other reasons, are not considered scary. If you were to give some examples of movies you found genuinely scary, then we would have a discussion.