Sal is starting to get pulled into Phoebe’s paranoid outlook on the world. So, things that normally wouldn’t scare her—like a young man at the cash register—are starting to look sinister. In this way, Phoebe seems to be influencing Sal to make negative assumptions about people she doesn’t know. Ben’s suggestion that Phoebe shouldn’t call the young man a lunatic (a term that implies that he’s crazy) suggests that Ben has some sort of negative association with this word and finds it offensive—perhaps because he or someone he knows has been called a lunatic before. Finally, Sal’s habit of flinching when people touch her implies that she’s pulling away from people emotionally. She’s afraid of getting too close, perhaps because Momma (the person she was closest to) left her.