How does Bigger feel towards Mary and Jan when he first meets Jan? Why do you think he feels the way he does?

It would be an understatement to say Bigger is made uncomfortable by Mary and Jan. The initial reason for this, on the surface, is that he is supposed to be driving Mary to the university, and she changes the plans on him, so that Bigger is forced to do something not on the up and up. But a deeper cause of his discomfort is the way Mary and Jan behave toward him. The attempted familiarity with which they act throws him off balance, and he doesn’t know what to make of it. He might have expected them to treat him in a stereotypical fashion, coldly ordering him about, which would have been even worse, of course, but would still have been the comportment of white people Bigger would have been familiar with. Instead, their attempt at kindness and intimacy, if that’s what it is, backfires.
Based on what he has seen in his life to this point, Bigger has little reason to believe Jan and Mary are sincere in their behavior to him. The whole situation is acutely embarrassing, especially because of their obviously condescending manner, despite their apparently good intentions. Jan and Mary begin to talk about “the Negroes” as if Bigger isn’t even there, asking each other “do you know any Negroes” and similar things as if discussing some kind of scientific study. It increases Bigger’s resentment and his wish that he were somewhere else, anywhere but in a car with clueless people.