It killed Johnny to see Robby in juvie. It represented all of his utter failings as a father. He'd hoped Robby would turn out better than him. But what was hope without action?
He should've paid closer attention to the path Robby'd been walking, rather than trust LaRusso with him.
He wanted to say he was sorry. Of course he was. But Robby had heard that a million times before, hadn't he? What did that word mean to him anymore?
It must've still meant something, because Robby said it first. "I'm sorry, Dad. About Miguel."
Johnny's voice cracked. "I know."
