We all look to have transcendent experiences that lift us out of the everyday, and fear is a good one. But, I think it's the same reason why people want to laugh their heads off.
I can't imagine that I would have been cast in the role, without Jamie Lee giving me a thumbs up.
I think that was the case here. We just wanted it to be good for everybody.
I think in the case of horror, it's a chance to confront a lot of your worse fears and those fears usually have to do, ironically, with powerlessness and isolation.
The idea of it becomes a little freaky if you're dealing with someone who has trouble differentiating between fantasy and reality, but that's a concern no matter what kind of movie you're dealing with.