Romeo and Juliet are both immature and passionate, which leads them to be impulsive.
Romeo and Juliet are both pretty moody. Each feels that their family’s feud is foolish, and their parents interfere too much in their lives. Juliet does not want to marry Paris, the man her father picked out. Romeo does not tell his father what is bothering him when Rosaline dumps him. Neither one feels that their parents understand them.
Their falling in love was rash and romantic, since they each loved each other from the first time they met. Romeo snuck into Juliet’s yard and basically proposed, and she basically accepted. However, she asks him to wait.
Although I joy in thee,
I have no joy of this contract to-night.
It is too rash, too unadvis'd, too sudden;
Too like the lightning, which doth cease to be(125)
Ere one can say ‘It lightens.’ Sweet, good night! (Act 2, Scene 2)
This instant marriage proposal between two young people who either were or are supposed to be in relationships with others demonstrates the impulsivity of their decisions. Juliet does exhibit some common sense by telling Romeo that a real proposal or acceptance would be worthless in this situation, but they still marry in secret soon after meeting.