Given how Mansfield believed in the idea of "risk, risk everything," she would hope that Lelia would not define herself in the context of the evening's ball. I think that Mansfield would want Leila to put aside the "The lights, the azaleas, the dresses, the pink faces, the velvet chairs," and recognize that social notions of the good do not define her being. The fat man's insistence of the terrors of age do not have to be fulfilled. Leila can "risk everything" and be her own person apart from the trappings of a conventionally dictated existence. Leila does not have to be an extension of this social world, but rather can repudiate it in living a life after the ball that does not make itself so dependent on it.
In figuring out Leila's thoughts and feelings from the text, one has to go back to the moment that ends it. Mansfield writes that Lelia "smiled at him [the Fat Man] more radiantly than ever. She didn't even recognise him again." Does she fail to "recognize him again" because she has realized that she will not allow him to define her or does she forget about him because Leila is enthralled with the ball, the moment, and she fails to acknowledge anything else? The answer to this probably demtermine how one reflects about Leila after the ball. If one concludes that Leila has adopted a position of resistance and will not be defined by the socially constrictive comments of "the fat man," then Leila will probably go home after the ball and recognize the moment for what it was and live her life in a manner that she wishes. She will "risk everything" in repudiating the socially constructed world of the ball. Leila will go back to the small owls and the countryside and find her happiness. If Leila has forgotten the fat man because of reveling in the moment, Leila might wish to return to this moment, experiencing the instant like a narcotic. In this light, her thoughts and feelings about the ball are simply to return to it. It is here in which reflecting about Leila after the ball becomes dependent on how one views the ending of the story.