Comic relief provides an interlude in a tragic world. In Romeo and Juliet there are two comic figures, the Nurse and Mercutio. In fact, Mercutio is more than comic, and is such an interesting character that Shakespeare removes him in Act III because he threatens to overpower Romeo's character in personality and importance.
With her bawdy humor and ridiculous appearance, the Nurse is a figure who appeals to the groundlings at the Globe Theatre and continues their interest through the more profound passages. In Act I, she is silly, prattling about Juliet as a baby until Lady Capulet scolds her, "Enough of this."
Then, in Act II when the Nurse goes to meet Romeo as Juliet's envoy, she is the target of almost slapstick humor as Mercutio notices her abundant attire, shouting, "A sail, a sail!" After she returns in Act II, Scene 5, she toys with Juliet who is so eager to learn what has transpired, complaining of her aches and rambling again instead of telling Juliet what Romeo has said. When she finally informs Juliet that Romeo wants to marry her at Friar Laurence's cell, the bawdy Nurse teases her about their marriage night and what will happen as "climbing a bird's nest" is vernacular for copulation:
Hie you to church; I must another way,
To fetch a ladder, by the which your love
Must climb a bird's nest soon when it is dark.
I am the drudge, and toil in your delight;
But you shall bear the burden soon at night. (2.5.74-78)
A masterful comic, Mercutio teases Romeo continually and makes use of pun and bawdy jokes. His view of love is a counterpoint to Romeo's courtly love and unrealistically romantic ideals. In Act I, for instance, when Romeo bemoans his unrequited love from Rosaline, Mercutio makes the ribald observation that Romeo should go out and find a woman that will "requite" his passion with physical passion:
If love be rough with you, be rough with love;
Prick love for pricking, and you beat love down. (1.4.4)
Even as he dies in Act III, Mercutio goes out in comic fashion, making a pun upon the gravity of his wound and using the language of the lower characters, rather than speaking in verse:
No, 'tis not so deep as a well, nor so wide as a church
door; but 'tis enough, 'twill serve. Ask for me to-morrow,
and you shall find me a grave man. I am peppered, I
warrant, for this world. A plague o’ both your houses!
Zounds, a dog, a rat, a mouse, a cat, to scratch a man to (3.1.97-103)--