Sally is a girl whom Holden has dated on and off, an extremely conventional teenager with conventional desires and aspirations. Although Holden considers calling Jane before calling Sally, he opts to call Sally instead, presumably because a rejection from Sally would not hurt as much as a rejection from Jane. Holden doesn’t respect Sally as much as Jane, calling Sally “the queen of the phonies.” Throughout their date, it’s abundantly clear that Sally is less interested in Holden himself and more on going through the motions of having a nice date. She’s excited to go to the play with Holden because a famous and popular actor couple is starring in it. Instead of discussing the play with Holden, she discusses it with George, who goes to an even more prestigious boarding school than Holden. She’s excited to go ice skating even though she doesn’t know how to ice skate because she likes the idea of renting a cute skating outfit. She is precisely the kind of person that Holden looks down on.
As Holden appears quite aware that he doesn’t have feelings for Sally beyond physical attraction, his attempt to initiate deeper conversation and even propose running away with her is confusing to even Holden himself. We can read this moment as symptomatic of Holden’s breakdown, a cry for help in his loneliness. He could also be expressing to Sally what he really wants to say to Jane, whom he respects and wishes he could date. Regardless, Sally takes his words at face value and therefore only sees Holden behaving strangely and rudely. Sally, of course, has no reason to look deeper into Holden’s behavior, especially given the shallowness of their relationship, and her distress is quite reasonable. Her outrage makes it more abundantly clear that they are speaking in different registers: Holden existentially, and Sally in that of social conformity. Their date therefore only makes Holden feel more alienated.