The Thing in the Window

I haven't been a big reader of horror until fairly recently, so some of the stuff I post here will no doubt seem very basic to experienced readers and writers of suspense. But I've got to start somewhere, so we'll begin with the "Thing in the Window."

I've noticed that this technique appears with some regularity in the few books I've read over the past few weeks, and it works something like this:

The hero/heroine is alone in a house (preferably some place where they feel especially vulnerable and where their own privacy is usually assumed). There's some business with the hero/heroine worrying over some earlier development in the story or perhaps some disturbing aspect of their past--a relationship gone bad, whatever.

As the protagonist is going about their business, fretting over whatever it is they are fretting over, they are also engaged in some mundane activity (preparing for a bath, making tea, toweling off the dog after a lonely walk in the rain), when they are suddenly overcome by some vague, bone-chilling, sense of dread. They are overpowered by the uncanny terrifying sense that something is watching them, something malevolent, something evil.

The protagonist chances to look up at the bathroom window (or the kitchen window, or the bedroom window), and there it is! A dimly-defined face expressing malice, or hatred, or agony, or some other unpleasant, disturbing emotion.

Then it's gone! Just like that.

And for the rest of the story, we repeatedly find ourselves in situations where one of two things happens:

1) The thing pops up again, or
2) The protagonist is in another situation where the thing might pop up again, and it doesn't. But the protagonist keeps worrying about whether it will pop up again, what it means, etc. So even if it doesn't pop up this time, we are left with the unsettling sense that it might at any time.