Esperanza realizes that the judgement of others who do not live in the barrio is even worse than her own shame at her heritage and poverty.  Sister Superior unfeelingly assumes that she lives in the worst part of the neighborhood, even worse than the humble reality of Mango Street.  Also, she realizes that eating in the canteen, the prize for which she subjected herself to the nun's interview, is nothing special.  The other children only stare at her as she cries and eats her poor sandwich, and she comes away from the experience feeling more isolated and ashamed than ever.