is it because we don't know what is the in the dark?
I think because the dark relates to the colour black and there are a lot of creepy things that are black. Also horror movies put the picture in our minds. Theres always scary things happening in the film at night in the dark. In a way, its mysterious. You dont know whats there, you feel anything is going to grab you or someones hiding under the bed. Also characters like the Boogeyman affect some people which makes them think of the dark as scary where bad things hide. Once I was on a school camp and this group of girls were playing truth or dare and they dared my friend to call the Boogeyman in the dark. She was afraid but she did it anyways. She was so scared even though she doesnt believe in the Boogeyman and now she is never seen in the dark. She has a phobia of the dark. She claimed the whole horror movies and thrillers and the stories and myths she heard about people having thing happening to them in the dark scared her. So I guess the media and myths have a large impact on the "dark" and why it can be scary. Also you cant see much in the dark and any sound you hear or movement would scare you.
a fear of the unknown, you cant see whats in the dark, and that scares a lot of people...wether your scared of there being someone in he dark or even something in front of you that you might hurt yourself over or fall on, its a fear of the unknown
As being blind is always scary, so is being in the darkness. It is not the creepy things that most people worry, but it is being not knowing what is around you.
What frightens me is not the the darkness, but a sound of silents in the darkness! Not knowing is not my fear, it is silents.
I thin it is because we can't see and what we can't see frightens us...
That coz dengerous things happens by night
Good answer :P