Epigraphs are like little appetizers to the great entrée of a story. They illuminate important aspects of the story, and they get us headed in the right direction.
So that ye may have
Clear images before your gladdened eyes
Of nature's unambitious underwood
And flowers that prosper in the shade. And when
I speak of such among the flock as swerved
Or fell, those only shall be singled out
Upon whose lapse, or error, something more
Than brotherly forgiveness may attend.—William Wordsworth, The Excursion, Book VI, "The Church-Yard Among the Mountains"
Things William Wordsworth liked: daffodils, peasants, long walks, and talking about himself. Things William Wordsworth disliked: poems and stories that were elaborate, unrealistic, and cheaply entertaining. As you can see, we'd be great at helping Wordsworth write his OkCupid profile.
And we have a funny feeling that, if they'd had OkCupid in the 19th century, Wordsworth and George Eliot would have been paired off like that. Both were interested in depicting flawed characters with compassion and dignity. Wordsworth's ambition to deliver "clear images" of lowly and ignored stretches of society is something Eliot identified with completely… and something that she focused the novel Adam Bede around.