The irony of projection
The play is designed to explore some unfortunate habits that people sometimes resort to in their relationships. The play focuses on the ironic nature of projection. Monica clearly criticizes others based on her internal battle to believe positively about her own self. She uses critical projections so that she can be an alpha, because that makes her feel safe.
The irony of domination
Clearly, Monica often dominates her sister. Because they are siblings, we know that Monica and Claire shaped their personalities in twain, probably through conflicts with the other person. The irony in the scene is that Monica feels more free to dominate her sister, because they have established rapport. But she straight up tells her, "Shut up," at one point, because Claire decided to speak when it "wasn't her turn" or something. Domination is ironic because people often try to control the people they should be loving.
The irony of masturbation
Although masturbation feels morally wrong, is it? In this play, the action of self-pleasure is actually a metaphor for shameless love and acceptance of one's self. The ironic reversal also shines light on a serious issue: these women are systemically repressed by the cultural views of their life and its context. Ironically, they struggle to feel enough ownership of their body to explore it.
The irony of Rockwell's paintings
There is a major use of irony in the scene where the girls discuss Norman Rockwell. The allusion serves to remind the reader of a dark irony. Although Rockwell's portrait of American life is undoubtably sweet and nostalgic, it is also sublime and horrific in its depiction of ennui and loneliness. These girls understand that irony in their own lives, because their attempts to find happiness are constantly obfuscated by their residual belief in the American Dream.
The ironic tip
This irony is an urgent reminder to the reader to forgive Monica's brash dominance. After all, both women are in the same shoes: both are somewhat repressed, both struggle with self-love and feelings of shame. The story encourages the reader to criticize Monica for her critical perspective, but then Monica leaves an impressive tip for the waitstaff, invoking the theme of mutual support and redemption.
