In chapter 7 of The Great Gatsby, why does Nick change his feelings toward Jordan? What were his feelings before?

Nick's feelings about Jordon before chapter 7 of The Great Gatsby tended toward a sort of amused curiosity laced with affection.  After all the events that took place in the previous two chapters in particular, Nick is no longer amused by the spoiled, self-centered crowd Jordan is a part of.  He is now disgusted with these people, Jordan included, because he sees them for the shallow, self-absorbed, immoral people that they are.