The next morning Holden calls up Sally Hayes. He says that Sally is a girl who seems intelligent and sophisticated, but is actually stupid. He makes a date with her for that afternoon.
If she seems smart, why does Holden think she's stupid? Because she dates boys like Holden.
Holden checks out of the hotel and goes to Grand Central Station to store his bags in a locker, and thinks of his family: his father is a successful corporate lawyer, and his mother has been nervous and ill since Allie died. He worries what his expulsion from Pencey will do to her.
Holden's father is the kind of phony Holden dislikes. His mother has perhaps suffered a nervous breakdown similar to Holden's.
While having breakfast at a sandwich shop, Holden meets two nuns carrying cheap suitcases. He talks with them, though as they discuss Romeo and Juliet he wonders if they're comfortable with its sexual content.
Note the contrast between Holden's words and his thoughts: adult sophistication vs. adolescent fixation on sex.
Though low on funds, Holden gives the nuns a ten-dollar donation. After the nuns leave, Holden wishes he had given them more than ten dollars. He decides that money always ends up depressing everybody.
Another contradiction: Holden makes a donation to nuns after describing himself as an atheist. He has positive feelings for any non-sexual women, but his depression clouds even the most pleasant encounters.