Music and songs both add to and, at the same, undercut the festive atmosphere of this play, which celebrates the holiday of the twelfth and final night of Christmas. The play opens with a song ("If music be the food of love, play on”), and four songs within it reinforce the underlying melancholic theme that simmers beneath the madcap comedy: time is short and speeds by quickly, so let's grab love and pleasure while we can.
For example, the song sung by Feste in Act II, scene 3, "O Mistress Mine," openly articulates the "carpe diem" or "seize the day" theme that underlies much of the play's merriment. We are merry because our time on this earth is short. Feste sings:
What's to come is still unsure/in delay there lies no plenty/then come kiss me . . .
In "Come away, come away," the song Orsino wishes sung in Act II, scene 4, Shakespeare is able to express more openly the theme of sexual desire. He plays with the idea of "death" as both orgasm and the end of life: both life and love pass quickly. In Act iv, scene 2, the song "Ah Robin" mourns unrequited love, and the lyrics also emphasize that a woman's love is not long-lasting: it is "but a blast . . . that turneth. " The song "When that I Was" at the play's end is also about time's passage: "A great while ago the world begun . . ."
The songs provide a context that add a bittersweet note to the play, being at once both celebratory and melancholy.