One of Juliet's traits is stubbornness, which is especially seen in her desires to know her own mind and do her own will. We even see her stubbornness in the very first scene in which we meet her. Due to the time period, it is Juliet's responsibility to play the role of a dutiful daughter to both her parents, willing to do their bidding. In Act 1, Scene 3, we actually see that Juliet feels conflicted between her role as a daughter and her role to herself. When Juliet's mother asks Juliet to pay attention to Paris at the ball that night to see if she can like him, we especially see Juliet's budding stubbornness and her conflict between duty and self in her response:

I'll look to like, if looking liking move;
But no more deep will I endart mine eye
Than your consent gives strength to make it fly. (I.iii.101-03)

In these lines, Juliet is playing the role of a dutiful daughter by saying "yes" to her mother, but just barely. Her "yes" is canvased in an "if" clause. In other words, she's saying, "yes," she'll look to see if she can like him, but only if looking at someone can really determine whether or not you can like that person.

One of Romeo's traits is that he is a bit irrational and emotionally driven. We especially see his irrationalism in the very first scene. When he moans to Benvolio about his heartache over Rosaline's rejection, and Benvolio begs him to listen to his council and forget about Rosaline, Romeo's only response is, "O, teach me how I should forget to think!" (I.i.228). This is a very irrational and emotionally driven response. A wiser man than Romeo, like Benvolio, would understand that being rejected is not the end of the world, that allowing himself to continue to feel brokenhearted is unhealthy, and that it's time to move on. Hence we see that one of Romeo's traits is irrationalism as well as emotionalism.