What is the appeal of horror?

People like to be 'jumped out of their seat' when they see a horror film and i feel the main thing that appeals to the audience is 'fear'. We all have nightmares in real life and try to block them out but, in a film you can always say afterwards that it is not real. So overall i think that we are attracted to the horror genre because we can watch somebody else be frightened and scared in a film and no at the end of it, it does not affect us and also, it is not real!