What passage highlights a setting & how does that setting establish the atmosphere & mood of the scene?Besides the valley of ashes. I was thinking...

Many places in chapter 3, the first chapter that describes one of Gatsby's parties, indicate that people had fun at Gatsby's parties. About midway through the chapter, Jordan and Nick have just bumped into the elusive Gatsby who is called away almost as soon as he introduces himself to Nick.  Nick is still pondering his host when Jordan says, "Anyhow he gives large parties."  This begins a passage that shows the people enjoying themselves.  It is shortly after that passage, that Jordan is summoned - alone - to speak with Gatsby and Nick is left alone.  People at Gatsby's party in this chapter speculate endlessly on their host and it is clear they know almost nothing about him other than the fact he is their generous host.  He makes very few appearances and calls no attention to himself at his parties.  It is after Jordan speaks with him in this chapter that we begin to discover the purpose of his parties.