How does Saki use satire in "The Open Window"?

In "The Open Window," as with many of his short stories, Saki effectively satirizes the manners and habits of the upper classes in Edwardian England. Behind the thin veneer of formal politeness, there always seems to be something vaguely sinister going on beneath. In other words, all seems respectable and civilized, but in reality there's something rather forbidding and intimidating about the way such people treat outsiders.
And so it is with "The Open Window." Framton is made to feel rather uncomfortable by Vera before he's even had time to sit down during his visit to the Sappleton residence. Things don't get much better as Vera proceeds to scare the living daylights out of him with her horror story.
When Mr. Sappleton arrives she engages in brief conversation with Framton. Though formally polite, she still has a sense of hauteur about her, barely stifling a yawn as Framton regales her about his nervous condition. She's treating Framton with a similar degree of cool politeness as Vera, but one which scarcely conceals a contempt for the outsider, the city-dweller who doesn't understand the old ways of the countryside, particularly the long-standing tradition of superstitious folk tales.