So far thoughout the play Romeo have been more serious. When it comes to love Romeo is very Romantic and is constantly in love. He doesn't seem to care about the feud or want to fight, and last he is a poet that uses his words wisely.
Mercutio is hardly ever serious and is constantly making jokes and mocking people. He doesn't care for love and doesn't believe in it as much as Romeo. Mercutio seems to care more about the feud and is much quicker to pick a fight. Last Murcutio doesn't use his words the same as Romeo. Romeo talks in sonnets and poems while Mercutio makes puns and jokes.