In Chapter 8 , How is Nick's attitude towards Gatsby ambivalent even at the moment when he says goodbye to him?

Gatsby is lost in his fantasy. He is lost in the illusion that Daisy will come back to him and they will live a meaningful life. Like the green light, Gatsby waits for Daisy as if his hands were still outstretched. Nick has pretty much had it. Gatsby is lost in his fantasy world and Nick can't pull him out.