The play’s central tension is that Romeo and Juliet’s love exists entirely inside a structure built on hatred — their families’ feud. Nearly every act of love in the play (the marriage, the potion plan, Romeo’s final act) is also, indirectly, an act of defiance against that hatred.

Mercutio’s dying curse — “a plague o’ both your houses” — makes explicit what the plot demonstrates throughout: that the feud, not any individual villain, is the real destructive force in the play.