"micro-agressions," those things that white people say to non-white people on an everyday basis.
(My daughter, for example, has people say "What are you?" when she meets them. On the first day of the summer camp she might be chosen last in team sports, as short half Asian girl. The next day she will be chosen much more quickly, since she is very athletic.)
I have found the chronicles of such grievances unconvincing, in the past, but I think I have been wrong. You cannot consider the micro-aggression in isolation. After all, if I am a black woman and have had one insult in my whole life, that it not very realistic. It is the constant litany of them that get obnoxious, I would imagine.
She reports that a friend said "I didn't know black people got cancer." Rankine cites this as de-humanizing. I don't doubt it. Does the person think that black people have some special gene that makes them immune from cancer? Probably not. Rather, the person is just not thinking at all, but falling back on an image of the "cancer patient" as a white person. It is not racism as hostility, but racism as pure stupidity. Of course, the white person who says this is probably an intelligent liberal who would never be racist in a deliberate way.
Rankine goes to her therapist's house for her first appointment. When she rings the doorbell, the therapist yells at her to get off her property. Why? Their conversations have been by phone, and the therapist is not expecting a black client. Once again, the therapist is not a KKK racist, but somehow did not have the image of an African-American woman in mind as a potential client of hers. This example is very similar to the "cancer" anecdote. What comes into play is the "universal" image of someone with a particular situation. If I ask you to think about an alcoholic, maybe you will picture a white male.
A third anecdote: Rankine is in a car with someone, presumably a dept chair, who says that he is forced to hire a person of color, even though there are great writers (presumably not "of color") that he could hire instead. Here, the interlocutor assumes that the white male is universal, even when he is talking to the non-male, non-white person.
It doesn't even matter whether the category is positive or negative. The cancer patient, the person in need of therapy, the "great writer" are prototypically white. The mistakes here are cognitive, intellectual. They don't stem from overt racism, but from a kind of stupidity. We might all fall victim to moments of perfect idiocy like this, but I am thinking that intelligence itself might be a kind of ethical imperative.
Baudelaire's friend (in one of his prose poems) gives a counterfeit coin of considerable face-value to a beggar, thinking that this is a win-win. The privileged individual doesn't lose anything, since the coin is worthless, and the begger gets something: the possibility of passing the coin along without being detected. B. has a fit, thinking that this act of beneficence / malice is completely stupid. The problem is that the supposed act of charity could bring the beggar unforeseen consequences:
Je le regardai dans le blanc des yeux, et je fus épouvanté de voir que ses yeux brillaient d'une incontestable candeur. Je vis alors clairement qu'il avait voulu faire à la fois la charité et une bonne affaire; gagner quarante sols et le coeur de Dieu; emporter le paradis économiquement; enfin attraper gratis un brevet d'homme charitable. Je lui aurais presque pardonné le désir de la criminelle jouissance dont je le supposais tout à l'heure capable; j'aurais trouvé curieux, singulier, qu'il s'amusât à compromettre les pauvres; mais je ne lui pardonnerai jamais l'ineptie de son calcul. On n'est jamais excusable d'être méchant, mais il y a quelque mérite à savoir qu'on l'est; et le plus irréparable des vices est de faire le mal par bêtise.