The tone of the titular essay "Notes of a Native Son" in Balwin's collection is incredibly tense. In this essay, Baldwin is dealing with his near hatred for his father even as he simultaneously struggles with American white supremacy. The story he relates about the diner encapsulates the mood of this essay as the hatred that has boiled up within him in response to racist policies and attitudes errupts in an explosive display of violence. It is this violence that bubbles just under the surface for many African Americans that Baldwin is seeking to understand. Such tension is also manifest when he relates his father's funeral, which takes place on Baldwin's birthday as well as the birth of his newest sibling. Death and life clash in this scene in a way that doesn't quite have a resolution, though Baldwin does reach an understanding of his father that abates the hatred--a development that speaks of tentative hope for the violence of life in racist America.
It is important to note that this essay is not one written out of anger, but one that tries to understand anger and its role in daily life. The tense tone of the essay is consequently not the result of bitterness, but the result of Baldwin's nuanced study of himself and his complex motivations and reactions.