Have you looked under your bed lately? Have you looked behind the couch recently? What about that one storage closet, have you looked inside on the last day or two? When was the last time you opened that one semi-hidden side cabinet in your kitchen?
Have you been up in the attic lately? How about the basement? Did you check behind the refrigerator? Under the floor boards? Between the walls or beneath the patio? On that shaded bit of the roof that can't be seen from the ground?
Do you look up often? Have you looked behind yourself lately? Are you always aware of your surroundings when you're alone? So, so naively alone?
Can you ever be entirely sure that there's nothing there?