This is the only movie...
...that actually scares me enough to where I have to stop watching it, sometimes. I'm the type who's not impacted by slasher movies, because I always think in the back of my mind that if I had someone chasing me, I'd just shoot the SOB. Ghost oriented movies, to me, are predictable or silly, and thus don't impact me. Movies about Satan only have limited effect. But any movie about the damned afterlife, stuff that can't be figured out, or analyzed. Those movies get me all the time. This one, bar none, is the best.
When I first saw this one, I actually couldn't sleep for a few nights. No movie since then has had that effect on me. JL is the only move that has ever psychologically bothered me enough to where I can't always watch it.
Good movie.