Koji Obata, the protagonist of Hiroyuki Agawa's novel, tends not to feel strongly about things. He is, however, convinced that this detachment is an aspect of his character that he'd like to change. Early in the novel he decides that "he [is] looking for something he could confront openly, something — immoral or not — that could really engage his emotions." He has this realization after a couple of visits to prostitutes convince him that casual sex will not give him the emotional frisson he seeks.
He wouldn't be the first to find commercial sex less exciting in practice than in anticipation, but things that would get a significant reaction from most of us — the atomic bombing of one's hometown, for example — leave Koji, who is in China when his native city is destroyed, more or less unmoved. Reading in an article immediately after the event that "everyone in Hiroshima must be dead ... Koji felt no surge of melancholy or anger, only the sense that what was to happen had happened."