Dr. Bledsoe represents cynicism and disillusionment; while the narrator is optimistic at this stage in his journey because he doesn't yet recognize the ways in which the world to which he seeks to belong has already rejected him.
Both Dr. Bledsoe and the narrator's dead grandfather share in common a feeling that they have to manipulate white people "with grins and yeses," that they have to learn to anticipate white people's needs and moods, as modes of survival. Dr. Bledsoe grows angry with the narrator, thinking him a fool, because the narrator has not yet learned this lesson.
Mr. Norton, the college's benefactor, has asked to go out to the former slave quarters and the narrator, whom Dr. Bledsoe has appointed as Norton's driver, obediently takes him there. In the old quarters, Norton meets Trueblood, who tells them the story of how he has sexually abused his daughter, thereby evoking Norton's own secret wish to commit incest. The encounter leaves Norton deeply troubled. Bledsoe becomes angry with the narrator for not knowing that he shouldn't have given in to Norton's wishes, despite what Norton said he wanted. Blesdoe explains that white men like Norton don't know really what they want from black people, and that their expressed desires for authentic experiences of black life are really disingenuous.
One could argue that, due to a refusal to become like Bledsoe--cynical and dishonest--in order to succeed, the narrator rejects society altogether by going underground.