Question

Why does Shakespeare include this comic speech by Mercutio?

Answer 1

In Romeo and Juliet, Mercutio is there at the beginning of the play and tells Romeo to forget abut the girl he loves, Rosaline. He tries to get Romeo to find a different girl and so they go to a masquerade ball and he meets Juliet, his new love. 

I would say to develop character and to make the audience think it's funny, most likely. 

I hope that helps! 

- mathwizzard3

Answer 2

He is the foreshawdoing the time "has come"