Here's the scene:
* Mildred: "What are you rebelling against?"
* Johnny: (looking directly at Mildred with a slight smile) "What've you got?"
The line "What've you got?" is open to interpretation, but it suggests:
* A rejection of traditional values: Johnny is rebelling against the established order, which he sees as stifling and meaningless. He's looking for something more, something authentic, but doesn't know exactly what that is yet.
* A challenge to authority: He's not simply rebelling for the sake of rebelling, but against the way things are. He's questioning the social norms and expectations that are imposed upon him.
* A search for meaning: He is looking for purpose and identity outside of the conventional path.
The scene emphasizes the ambiguity of Johnny's rebellion. It leaves the audience to ponder his motivations and the nature of his revolt. The answer lies not in a specific "what," but in a general questioning of the "what's there" in the world around him.