Interpretation? Imagination? Narration?

At first I did not like the tone and mood of the novel Seize the Day, I found it meaningless and boring. But once I got more and more caught up in the story I realized that the what makes the novel what it is, is the way it is written. In fact you have to be very careful because you might get mixed up between parts where the narrator is narrating and when it is actually talking almost in first person from Tommy's thoughts. So even though the story is being narrating from a different perspective there are parts where the story line is being interrupted by Tommy's thoughts or even what other people in the story think of Tommy such as Dr. Adler's opinion. This is the reason why the reader may sometimes not know the difference between whether it is an interpretation, imagination, or simply narration, it gives a confusing feeling between reality. 

From the way the narration and Tommy's thoughts develop, we can automatically tell that Wilhelm's life isn't the best one. As he descends to the lobby and stops at the new stand before meeting his father he has various flashbacks such as the one about Maurice Venice. From the choice of words and the description of his relationship with his father we can tell that he cares a lot about what his father thinks of him, and in his eyes he sees himself as a failure. Due to the fact that the novel is written the way it is, as if to say you might be confused about what is narration and what is opinion, we may even say that the description of Venice in the story at some point mixes with the description of Tommy himself. Of course the catch to this is that Wilhelm himself is giving the description, so we can infer that he's not very fond of himself. 

Also the reader is left we an intriguing feeling about how Dr. Adler actually is. At times he may seem like sophisticated retired doctor whom Tommy admires and at other times he seems like  a selfish, ambitious father who has never supported any of his son's decisions.