In Act 2, Scene 1, Mercutio treats love as a joke, showing us his view that love is a trivial, insignificant matter. We see Mercutio treat love as a joke when he decides to "conjure" Romeo into view through references to Romeo's lovelorn heart. Mercutio "conjures" Romeo by calling him several names he feels addresses Romeo, as we see in the line "Romeo! humours! madman! passion! lover" (9). Mercutio uses "humours" to address Romeo because he feels that Romeo's lovelorn state is "comic" and "absurd" (Random House Dictionary). Likewise Mercutio feels "madman" addresses Romeo because he feels that pining over Rosaline, or any woman, as Romeo is doing, is an insane action. Hence through this one line, we see that Mercutio's view on love is that it is not an emotion to be taken seriously.
Mercutio also shows that his view of love is that it is a purely sexual feeling and nothing deeper. Mercutio portrays this view through all of his lewd, sexual jokes in this scene, such as his references to Rosaline's anatomy:
By...her scarlet lip,
By her fine foot, straight leg, quivering thigh,
And the demesnes that there adjacent lie. (20-23)
In these lines, the word "demesnes" can be translated as regions, referring to sexual anatomy. An even more sexually suggestive reference is seen in his lines "O that she were / An open et cetera, thou a pop'rin pear!" (39-40).
Benvolio, on the other hand, placing more value on love and treating it with more importance, empathizes with Romeo's feelings, even though he does not think they are wise. We see Benvolio's empathy when he tries to shut Mercutio up, saying, "An if he hear thee, thou wilt anger him" (24). Benvolio's empathy with Romeo's feelings shows us that Benvolio's views on love are similar to Romeo's, even if he thinks Romeo is being foolish for allowing himself to continue to feel so brokenhearted.