Grandma Stannard (and why you shouldn't annoy the neighbours)

“Trick or Treat?” said the boy, in an annoyingly sing-song voice.
“It's April,” said Grandma coldly.
“And?” offered the boy.
And so begins the worst afternoon Grandma Stannard has endured for a long time. People just won't stop knocking on her door, trying to sell her everything, from double-glazing to Jesus. And we won't even go into her sudden vermin problem or the mysterious man in black and white. What in the world is going on?
A short story based (very loosely) on an old fairy tale.