The West End show “Avenue Q” famously has a song entitled, “Everyone’s a little bit racist”. It pokes subversive fun at our prejudice, our stereotyping and our subconscious biases.
Whilst in no way peculiar to this area, during my time in southern Africa I have been privy to numerous conversations which treat the subject of race; some with sensitivity and others with much blunter, discriminatory tones. 
I have heard white people judge black people and vice versa. In my opinion, we are all products of our environments and, although I found many of the racial comments to be offensive, none of those espousing these views were “bad” people. Many, if not all, were warm, generous and affable in many ways.
So why the animosity? Why the mistrust? As I tried to analyse the content of these discussions I noted one constant, one ever-present factor: generalisation 
I will couple this with the notion of categorisation. I lost track of the number of times I heard statements that began, “black people are/do….” or “white people are/do….” These statements suggest that it is possible to define the behaviours or personality traits of many millions of people simply through their ethnicity. Now try to think of two, just two, of your close friends who are similar enough to be talked about as a group, a category. Tough to do, isn’t it? And the category you eventually create is highly specific, (e.g. Open-minded introverts with a penchant for favoring the ideal over the real) certainly far more so than mere skin colour.
The other observation was that personal acquaintances were seldom included in the generalised slights. Many of those whom I heard spouting vitriol had friends or employees on the “other side” whom they trusted implicitly and felt to be good people. This seems to suggest a correlation – the better we know people, the more inclined we are to find good in each other. So, next time we make a judgment, a generalisation, let’s stop for a moment, pause to challenge ourselves, question the validity of our statement, before we speak. Opinions are worthless without reason.