I love watching a horror movie as it makes my increases my heartbeat and makes me on the edge of my seat.  Do you enjoy a good horror film?
omg, i really can't but if u convince me maybe I would 
Well, to start off, it's often inspired by a great author of the past, (i.e. Edgar Alan Poe, Mary Shelley), so you can always be assured that the storyline is there.
great I like allen poe
Next, horror films start playing with your mind and thoughts, overlapping the fantasy, the supernatural and the real world, blending it all into one.  That alone can give you a new sensation and feeling other films can't evoke.
Is there any regulation to curtail the amount of horror that can be in a movie?
Nope - but given the audience, you don't want it to be too gory or constantly scary.  A good horror film needs breaks in between to keep the audience guessing.  Then suddenly a ghost, aliens, vampires, demons pop out of no where.  
Amazing information, thanks, I would consider watching my first horror movie, thanks to you :)