In Chapter 3, the narrator graduates and tells his mother about his plans to be a distinguished Black man who "reflect[s] credit on the race." He comments that he would not come up with a real plan for doing so until years later, both foreshadowing his success as a ragtime musician and satirizing his own position as an "ex-colored man:"
For days I could talk of nothing else with my mother except my ambitions to be a great man, a great colored man, to reflect credit on the race, and gain fame for myself. It was not until years after that I formulated a definite and feasible plan for realizing my dreams.
The narrator flounders for a time after his graduation and his mother's death. Eventually, he does make a name for himself abroad as a ragtime musician, and he is on the cusp of great success with his music in the United States when he decides to pass for white. On the one hand, the "feasible plan for realizing my dreams" could refer to the narrator's plan to rewrite ragtime music in the style of classical music. But ultimately, this plan turns out not to be feasible: he decides that it is too dangerous to live openly as a Black man, and that it would be better to use his light complexion to become an "ex-colored man." Within the world of the novel, this decision is what allows the narrator to write his autobiography and become "famous" as an "ex-colored man."
Johnson uses the narrator's success in this endeavor to satirize the idea of "passing." Certainly not all fair-skinned Black people at this time chose to pass for white, especially not in all parts of their lives. But it was not an unheard-of phenomenon. White people were afforded far more economic opportunities and simple social respect than Black people, so those with light enough skin not to be classified as Black on sight might allow the world to believe they were white, at least from time to time. Johnson invites the reader to laugh at the idea that the "ex-colored man" has become famous. Technically, his autobiography does make him famous, but his anonymity throughout it means that no one actually knows who the real person behind this pseudonym is. He is a "great colored man" in that he travels the world and reports back on the experience of living in many places as a white-passing Black man. But he eventually refuses to live his real life as a "colored man" at all. The "credit" he reflects on Black people is negated by his refusal, once again, to live openly as Black. And yet, the only reason he is special or famous at all is because he has decided to become the "ex-colored man" and write about the experience. Johnson thus satirizes "passing" as a choice that may help people achieve their goals but that also empties those goals of meaning.
In Chapter 6, the narrator arrives in New York and uses a simile to foreshadow the dangerous life he will live at the "Club":
My blood ran quicker, and I felt that I was just beginning to live. To some natures this stimulant of life in a great city becomes a thing as binding and necessary as opium is to one addicted to the habit. It becomes their breath of life; they cannot exist outside of it; rather than be deprived of it they are content to suffer hunger, want, pain and misery; they would not exchange even a ragged and wretched condition among the great crowd for any degree of comfort away from it.
The narrator compares the effects of life in a city like New York to the effects of opium on somebody who is addicted to it. He describes the physiological rush he feels when he moves there, as though he is trying a new drug that he might come to depend on. While he first describes the feeling as "the breath of life," he goes on to describe the darker sides of addiction to the city. Like opium, the city produces cravings that drive people to put up with "hunger, want, pain and misery" if only they can continue living there. Even the promise of a comfortable place to live outside the city would not be worth the exchange.
The narrator is speaking in the third person when he describes these unsavory effects of the city, but he has already admitted that he felt the initial high that leads to dependency. It seems like only a matter of time before he falls into some of the unhealthy patterns he describes. Indeed, that is what happens: he takes up gambling and spends all his time at the "Club." While he is able to develop his expertise on ragtime while he is there, he also nearly dies when the rich widow's companion pulls out a gun in a jealous rage. The narrator only leaves when the millionaire promises him travel to even greater cities, such as Paris and London.