It seems I missed this thread as well. There are a few new ones for me in here.
I have been watching horror and other supposedly creepy or scary stuff since I was tiny. Most of these types of films don't scare me. The films that do are probably not what most people would expect, and not for reasons most would understand. One of the films that scared me the most was a comedy. Anything with certain 8 legged creatures bothers me, so Arachnophobia worked I guess, but so do some of the nature shows I watch...or going out my front door where the spiders like to hang out. I don't know what genre it fits into, but the spiders in Penny Dreadful piss me off every time. I should probably get caught up with it.
Back when I was very young I used to pretend to be all the bad things dwelling in the dark. It didn't work out so well, as I would run into everything and trip over stuff. I was more the clatter and crashing in the night than the bump. I doubt I was scary unless someone was concerned about things that might get broken, or paying medical bills for injuries I was lucky enough to avoid.
I do like that some TV shows and movies are trying to return monsters to being things that want to kill or consume you, rather than have sex with you. Check out The Strain if you also like that. I am looking forward to Fear the Walking Dead.
I haven't heard anything about the At the Mountains of Madness film in a while. I would love to see that made successfully.
For those that are scared by horror movies, why do they scare you? I have been startled by some (quiet scene with nothing going on then something jumps out along with loud sounds...I usually expect this now, so it doesn't work too well anymore most of the time.), but not much else most of the time.