The Question and Answer section for Short Stories of F. Scott Fitzgerald is a great resource to ask questions, find answers, and discuss the novel.
You can check them out at the GradeSaver link below:
Ww get the sense that perhaps she does not take Dexter seriously or that he is beneath the standard she usually dates.
Judy invites Green to dinner. He comes from a poorer background than Judy. He does not have the family "pedigree" that she does. He does not want to dress or act carelessly to turn off Judy, his love interest.