Mercutio's significance in Romeo and Juliet is evident even well after his death. There are many reasons why he is such an important part of the story and our understanding of the play. He shows another perspective on the theme of love with his cynicism. Shakespeare has made Mercutio as a foil for Romeo and a reference point between the two families, but he makes sure the audience doesn't forget about him. The death of Mercutio is a major turning point in the plot where we know nothing after will ever be the same.
Love is downplayed by Mercutio with cynicism. He believes that love is merely a path people to take for sexual gratification. Mercutio is also fairly hostile towards women and female sexuality and this is evident throughout the play when Mercutio talks about them or to them. Almost every time he mentions women or love, his speech is riddled with sexual innuendos and puns. "And to sink it in, should you burden love…" This is his advice to Romeo that if he keeps blaming love for his suffering, he'll sink further in love. But it also translates to them as if he means that if Romeo has sex with the girl that is troubling him (Rosaline) he would put a burden on her. He rattles out a string of puns when he talks about the Nurse “No hare, sir, unless a hare, sir, in a Lenten pie – that is,/ something stale and hoar ere it be spent.” meaning she’s an old, ugly, prostitute, much like a stale and mouldy pie: you’ll want your money back after consuming it.
Mercutio’s Queen Mab speech starts as an energetic, funny lecture mocking Romeo that seems like the lead-up to a fairy tale, but quickly dissolves into dark depression.
This is the hag, when maids lie on their backs,
That presses them and learns them first to bear,
Making them women of good carriage
This quote is, again, about sex, specifically that virgins are made to dream about sex and childbearing by this Queen Mab. The name itself is a sexual entendre stemming from the Old English way of calling whores...