Shakespeare's comedy, A Midsummer Night's Dream, tells the story of young lovers and a troupe of actors, caught in the woods after dark, at the mercy of mischievous fairies who turn the humans' lives up-side-down, if only for a night.
Shakespeare wrote his plays for an Elizabethan audience who totally believed in a supernatural world of witches and fairies. Critics credit Shakespeare with making fairies friendlier creatures than they had been perceived of before. Prior to Shakespeare's portrayal of fairies as child-like creatures—and their rulers Oberon and Titania as parent-figures to humans—fairies were believed to be evil.
In his article, "Shakespeare's Fairies: The Triumph of Dramatic Art," William J. Rolfe writes:
The fact is, Shakespeare was but slightly interested in the human characters of the present play...It was the fairies who chiefly attracted him, and on whom he lavished the wealth of his genius. They have been aptly called "the favourite children of his romantic fancy..."
These critics applaud Shakespeare's ability to create such "fanciful" creatures as Rolfe declares that Shakespeare's pleasure in character development for this comedy centered not around the humans, but the fairies; and it is, in fact, in their domain, that most of the play's comedy occurs.
Rolfe goes on to describe the characteristics of the fairies:
...in some respects they are like human children. Like young children before they have learned the distinction between right and wrong, they have no moral sense, and little or no comprehension of such sense in the mortals with whom they are associated. Like children, they live in the present...They think and feel like the child. Their loves and their quarrels are like those of the child.
What an excellent way for Shakespeare to approach these creatures: presenting them like children. Adults often view children's antics with humor rather than censorship, and we tolerantly chuckle over their games, arguments, and even the ways they try to impress.
The purpose of the fairies is to provide comedy, giving them child-like characteristics. The lovers in the woods fall in and out of love with the wrong people. The fairies play tricks on the actors practicing in the woods to scare them. In essence, the fairies entertain the audience by playing tricks on the humans—and each other (as Oberon childishly tricks Titania).
For instance, Oberon instructs Puck to use a "love potion" on the eyes of a "disdainful youth" (Demetrius) so that he will fall in love ostensibly with Helena. Puck "charms" the wrong man; when Lysander awakes, he sees and falls in love with Helena.
Content with Hermia? No! I do repent / The tedious minutes I with her have spent... (II, ii, 118-119)
Helena thinks he mocks her:
Wherefore was I to this keen mockery born? / When at your hands did I deserve such scorn? (II, ii, 129-130)
So begins the "comedy of errors" of humans controlled by the fairy world.
Even Puck's summation of the condition of humans affords a laugh:
Lord, what fools these mortals be. (III, ii, 115)
Lastly, because Oberon is angry with Titania, his wife, he sends Puck to her bower to charm her eyes. Puck turns Bottom into an "ass," and when she wakes, it is with Bottom she falls in love.
Pucks reports to Oberon:
My mistress with a monster is in love...An ass's noll I fixed on his head
Shakespeare's "children" (fairies) provide a grand source of comedy for his audience. This, then, is the role they have in the play.