I write short horror stories that play off of different irrational fears as children. for example, my first official story, The Mirror, plays off of the childhood fear of mirrors.
I've been writing stories my whole life. In elementary school, I used to write stories at my desk and the present it to the class for show and tell.
I wrote my first official story a few years ago during a summer program at UConn, an adaptation of the 2-line story "The last man on earth sat in a room. There was a knock on the door." (Unfortunately, that story is lost to the ages.)