Fantasy
Margot allows her crush on Robert to develop out of control based on their text message exchange, without thinking too hard about their actual in-person interactions. This is facilitated by Margot's trip home for break, where she stays in close contact with Robert, fantasizing about him constantly. When she returns, she is disappointed—first by his standoffishness, and later, by his inability to meet the standard she has created for him in her mind. This demonstrates how, early in relationships, people often set expectations for their partners that are based on subjective fantasies—fantasies that real, flawed human beings inevitably fail to live up to. Margot's experience thus shows the tricky nature of fantasy: it can be fun—even sustaining—in the early stages of a relationship, but comes at a risk, as real life hardly unfolds in accordance with our fantastic expectations.
Miscommunication
Margot and Robert's relationship unfolds primarily via text message. This allows them to grow close extremely quickly, but also fails to provide all the information that an in-person interaction might. The two are unable to test their compatibility or comfort with one another, so when they're reunited, they find that they don't get on as well face-to-face as they did via text. This demonstrates a certain kind of miscommunication: they know a lot about one another, yet at the same time, actually have fairly little idea how to interact with one another in real life. They also fail to communicate adequately about their age difference, as Robert reveals he doesn't know that Margot is too young to drink alcohol towards the end of the story. Some of the discomfort in their relationship might have been avoided with the aid of direct, candid communication to sort out these issues.
May-September Romance
Robert is fourteen years older than Margot. Though he doesn't seem to know her exact age, it's clear that Margot is in college, and Robert graduated several years ago, meaning the two are at significantly different places in their lives. Robert has more independence—his own home, for instance—whereas Margot still lives in a dorm with a roommate. This difference becomes challenging when Robert wants to take Margot out for a drink, as she is too young to drink legally, and they must find a bar that's lax enough to let her in. Their significant age difference also contributes to a power differential in their relationship, which Margot appears to become uncomfortable with towards the end of the story.
Rejection
After Margot and Robert sleep together, she finds that she is not actually attracted to him—she was really just interested in the fantasy version of him she engineered in her mind. She thus decides to end their flirtation, telling Robert she doesn't want to see him anymore. Robert responds with compassion at first, but maintains that he hopes she'll change her mind. When he sees her in a bar a month later, he texts her again, complaining that he misses her. When she fails to respond to his text, he grows angry, eventually responding violently and calling her a whore. This demonstrates the anger that often grows out of rejection, testifying to Robert's emotional immaturity.
Sexual Regret and Consent
Margot is uncomfortable throughout her sexual encounter with Robert, and it's clear that over the course of their rendezvous, she's lost interest. They sleep together after several drinks, raising the question of whether Margot could have fully consented to their sexual engagement. The power differential in their relationship that results from their age gap also brings into question Margot's ability to consent. With these factors in mind, it's possible to read that she has been manipulated, partially explaining her extended discomfort after their sexual encounter and her desire to distance herself from Robert. Even after breaking things off, Margot feels a strange sense of guilt towards Robert, questioning whether she might have been unfair or judged him too harshly. It is apparent by the end of the story that her perception of him has been clouded, both by their gap in age/life experience and by the fact that their relationship grew primarily via text.
