This theme can best be observed through the romanticism of the narrator and his complete infatuation with Mangan's sister, whom, after all, doesn't even have a name in this story to suggest just how insubstantial his dreams of romance with her are. Note the way that he transforms reality into something out of Arthurian legends in the market:
These noises converged in a single sensation of life for me: I imagined that I bore my chalice safely through a throng of foes. Her name sprang to my lips at moments in strange prayers and praises which I myself did not understand. My eyes were often full of tears (I could not tell why) and at times a flood from my heart seemed to pour itself out into my bosom.
Clearly, we are seeing a boy in his first flush of love. He treats the request to buy something from the bazaar as a noble quest and sees himself as some kind of knight errant. It is only when he reaches the bazaar that he sees it, and his supposed love, for the drab, insubstantial thing that it actually is and reality comes crashing down around him. Reality and fantasy are completely opposed in this novel, and for a time, the forces of imagination seem enough to keep dull reality at bay.