There are numerous reasons a black person might not want to have anything to do with a white colleague, and most of those reasons are founded in trauma. But one major reason a black person may be wary of getting close, or rejecting advances of friendship, is the suspicion of motives, and that the white person probably wants us to emotionally take care of them. I’ve encountered this myself. I can’t be friends with every white person who wants my attention on occasion being friends with white people is exhausting, not because it’s a bad thing but because of the way the world is set up, and the constant racial trauma we’re subjected to.