In Joyce's "Araby," the narrator tells of his epiphany in the final sentence of the work:
Gazing up into the darkness I saw myself as a creature driven and derided by vanity; and my eyes burned with anquish and anger.
The speaker realizes that he has been living under an illusion, that he has been blind (like the street he lives on), that he's been "dark" (like the bazaar is now), that he's been thinking about the so-called relationship he has with Mangan's sister far more than the relationship deserves.
The speaker sees that the famous Araby bazaar is nothing so grand, hears the trivial, silly conversation among the workers, is disappointed in some way in the articles for sale, and realizes that he, too, has been blind and dark and trivial, as well as self-important. In reality, Mangan's sister probably barely even knows he exists. And she doesn't even have a name in the story. The narrator gives up his studies, obsesses, suffers in his waiting, and then realizes how trivial he's been.