I just joined after probably over a year of lurking - huzzah!
I discovered this site thanks to a friend who showed me SCP-173. Being a person who has always had a fear of psychological and mysterious horror, naturally I didn't sleep that night*. Since then I have read hundreds of SCP articles, and I've finally decided its time I joined in with the site.
*When something makes me truly scared, it keeps me up all night thinking about it. Once, when I was younger (about 10, I believe), I spent the night UNDER my bed, because I was scared of a monster I had imagined which was ABOVE the bed (contrary much?). Every now and then I dream I'm being abducted by aliens, and I generally have nightmares if I sleep.
How I haven't had some kind of heart problem, I don't know. Funnily enough, I actually enjoy being terrified, it makes life much more exciting when you feel like you're going to be in excruciating pain from some unknown entity hiding around a corner.
Oh man, I really waffled for that long…I'd better stop.
By the way, I wasn't joking in that last paragraph. Look out of the window behind you. ;)