Dickens uses hyperbole in many of the descriptive passages in A Christmas Carol to enrich and enlarge the mental picture he is creating in the mind of his reader. Consider his initial introduction of Ebenezer Scrooge:
A squeezing, wrenching, grasping, scarping, clutching, covetous, old sinner! Hard and sharp as flint, from which no steel had ever struck out generous fire; secret, and self-contained, and solitary as an oyster.
Scrooge's first encounter with the Ghost of Christmas Present, which takes place in his own bedchamber, uses hyperbole to contrast the usual dark, dismal, dirty and aged appearance of the room with the vision that awaited Scrooge.
The walls and ceiling were so hung with living green, that it looked a perfect grove; from every part of which, bright gleaming berries glistened. The crisp leaves of holly, mistletoe, and ivy reflected back the light as if so many little mirrors had been scattered there;
The Cratchit's goose was not a large bird in comparison with many geese being consumed on that day. But the Cratchits react as if it was "the rarest of all birds; a feathered phenomenon, to which a black swan was a matter of course." The Christmas pudding, the final jewel in their Christmas dinner, is unveiled by Mrs. Cratchit as the others wait and take in the progression of aromas.
A smell like a washing-day! That was the cloth. A smell like an eating-house and a pastry-cook's next door to each other, with a laundress's next door to that! That was the pudding!