Shakespeare uses Romeo's dialogue to describe how he changes between Act 1 and Act 2.
Romeo is a very different person in Act 1, Scene 1 and Act 2, Scene 2. In Act 1, he is whiny and mopey. His girlfriend has left him, and he is feeling very depressed. In Act 2, he is in love. He has found Juliet, and he is on top of the world.
In Act 1, Scene 1, Romeo is in a bad way. When he meets up with Benvolio, asked by Romeo’s parents to talk to him, he explains that his girlfriend Rosaline is no longer interested in him. He laments love’s fickle cruelty.
Why, such is love's transgression.(185)
Griefs of mine own lie heavy in my breast,
Which thou wilt propagate, to have it prest
With more of thine. (Act 1, Scene 1, p. 16)
Romeo does not want to go to parties. He does not even want to leave his room or go outside in the daytime. He feels that life is not worth living if he does not have his girl. He also feels the sadness of the brawl deeply, regretting that the two families are fighting.
In Act 2, Scene 2, Romeo has made a complete turnaround. He met Juliet at her party, and now she is all he can think about. Spending not a lot of time thinking about it, he scales the orchard wall and spies on her from the courtyard beneath her window.
It is my lady; O, it is my love!(10)
O that she knew she were!
She speaks, yet she says nothing. What of that?
Her eye discourses; I will answer it. (Act 2, Scene 2, p. 38)
Romeo has gone from moping to being giddy with love. He is happy, excited, and completely in love. When Juliet accepts him and returns his love, he is thrilled. His life is now complete, and he is sure that nothing bad can happen again.
Romantics will appreciate Romeo’s turn as faith in love at first sight. Skeptics will suggest that he just feels about Juliet the way he did about Rosaline, and he will move on to another girl later. Either way, Romeo is a very different man between these two scenes.