Lifelong reader, recently turned writer, my friends were surprised when I turned to writing horror. They remember me reading a lot of Sci-Fi while growing up. And I did. But there was an awful lot of Fantasy, Crime, Mystery and, yes, Horror in the mix.
Though I do have a few non-horror stories in my head and fighting to get out (I started this ride writing a series of Sci-Fi shorts to read to my son at night), most of what I write about comes from the darker side of life. And unlife. I'm going to just keep sprinkling material onto the mulch pile in my mind and see what comes up.