There's a documentary I like to watch each year around this time. It is a tad dated at this point, because it only examines the history of the horror genre from 1910's to the end of the 2000's. Still, what it has to say about the genre is so strong that I am always fascinated by it.
One of the reasons I love the horror genre so much, is that it really examines us. As people, although this documentary in particular focuses on how the horror genre changes as our country changed over the years. It slightly focuses on other other countries too. Horror is our fears, our doubts and our anxieties reflected back at us. You see that as this film slowly follows us through the years, discussing what was happening in our country at the time. As people were coming back from World War I, the "monsters" in early films were regular men. As Germans and other Europeans artists were fleeing Europe to avoid the rise of European Fascism, they brought their old legends with them. As the Cold War heated up, there were many movies about "The Other." Many end-of-the-world type scenarios. So on and so forth. It really is amazing how the entire genre has always been an examination of us as people.
If you look at the horror movies made by other artists around the world, many international filmmakers have spoken volumes about their countries through the movies they make. Guillermo del Toro had lots to say about the Spanish and Mexican journey on this planet through his films "The Devil's Backbone" and "Pan's Labyrinth." The horror genre can almost be used as a history lesson, albeit the darker history that you don't learn in a classroom.
This documentary best describes why I think horror is an important genre. A genre I wish was taken more serious. A genre that I wish was considered for Oscars. These movies do speak for us, and they are by us.