Insofar as the fifth act of A Midsummer Night’s Dream has thematic significance (the main purpose of the play-within-a-play is to provide comic enjoyment), it is that the Pyramus and Thisbe story revisits the themes of romantic hardship and confusion that run through the main action of the play. Pyramus and Thisbe are kept apart by parental will, just as Lysander and Hermia were; their tragic end results from misinterpretation—Pyramus takes Thisbe’s bloody mantle as proof that she is dead, which recalls, to some extent, Puck’s mistaking of Lysander for Demetrius (as well as Titania’s misconception of Bottom as a beautiful lover). In this way, the play-within-a-play lightheartedly satirizes the anguish that earlier plagued the Athenian lovers.
Given the title A Midsummer Night’s Dream, it is no surprise that one of the main themes of the play is dreams, particularly as they relate to darkness and love. When morning comes, ending the magical night in the forest, the lovers begin to suspect that their experience in the woods was merely a dream. Theseus suggests as much to Hippolyta, who finds it strange that all the young lovers would have had the same dream. In the famous final speech of the play, Puck turns this idea outward, recommending that if audience members did not enjoy the play, they should assume that they have simply been dreaming throughout. This suggestion captures perfectly the delicate, insubstantial nature of A Midsummer Night’s Dream: just as the fairies mended their mischief by sorting out the romantic confusion of the young lovers, Puck accounts for the whimsical nature of the play by explaining it as a manifestation of the subconscious.