This reminds me of the time I came home late from work one night and we later found our front door wide open. I was in high school and worked as a restaurant/bar hostess and my parents were usually in bed by time I got home on the weekends. Apparently, shortly after I arrived my parents woke up to the terrifying sound of a man calling out to them. It was my neighbor, standing in our foyer to see if everyone was okay because our front door was wide open in the middle of the night while he was outside smoking. 

In retrospect I'm sure I was just negligent and didn't shut the door all the way, but at the time it was pretty scary. I was always pretty good about locking the door behind me.