In the novel Pride and Prejudice hyperbole, or exaggeration, helps the tone of the story become lighter and satirical by placing emphasis and intensifying particular traits of specific characters.
These characters are often representative of specific strata of society, and their particular roles as citizens are an excellent conduit for Austen to treat their characteristics with exaggeration in order to make their actions and their mannerisms, seem "over the top."
The key characters which are mostly satirized are Mr. Collins, a vicar with patronage from an aristocrat, and the aristocrat herself, Lady Catherine de Bourgh: A woman so full of herself that she is oblivious of everybody else. By giving them intense reactions, ridiculous mannerisms, and awkward conversations, Austen makes these characters weird and comical. It is like an invitation for the reader to join in the fun.
Similarly, the Bennet clan is satirized by being portrayed as a bunch of "simpletons" who cannot behave well in public. Mary is plain and desperate for attention, Mr. Bennet is a detached parent, Mrs. Bennet is a loud and nervous chatterbox, and Lydia is a boy-crazy loonie who even eloped with a soldier and left her family name stained.
Although the actions of the satirized characters are quite realistic, the fact is that Austen accentuated what was awkward in them, and allowed these traits to color her characters with a comical tone.