This scene shows the heart of the conflict between the Capulets and Montagues as well as the rashness of young men. It also foreshadows the play’s tragic conclusion.
Benvolio predicts a “brawl”: “For now, these hot days, is the mad blood stirring.” However, Mercutio seems to be looking for a fight, accusing Benvolio of attacking others over the smallest problems: “thou hast quarrelled with a man for coughing in the street, because he hath wakened thy dog that hath lain asleep in the sun.” This accusation mirrors the entire feud between the Capulets and Montagues. The audience does not even know why the two households clash, and battles break out over the slightest provocations.
Tybalt appears, and he and Mercutio refuse to listen to reason. They scrap until Tybalt slays Mercutio when Romeo attempts to make peace between the two. Mercutio famously declares, “A plague o' both your houses!” Though he started the altercation, he can see that this is a cycle of violence perpetuated by the two families who “have made worms’ meat of” him, just as they make “worms’ meat” of many others throughout the play.
Romeo sets on Tybalt “like lightning,” another example of youthful impetuosity. Romeo had tried to ignore Tybalt’s taunts, telling him, “[I] love thee better than thou canst devise.” Unfortunately, anger overcomes love, demonstrating the power of enmity. Even the peaceful are drawn into the conflict. Romeo condemns Juliet’s beauty for making him “effeminate” and weak in the face of a dispute.
Romeo senses that this is the beginning of the end for him: “This day's black fate on more days doth depend; / This but begins the woe, others must end.” The prince exiles Romeo for killing Tybalt, and Romeo kills Paris and himself after Juliet fakes her death. In turn, Juliet commits suicide. This scene is central to the the play’s themes of fate, tragedy, and violence.