Racism, skin colour.. I don't think humans will ever get over the difference in colour in different people. Not unless people of different colours are really forced to mix with each other. Like in singapore, people stick to their own racial groups most of the time, right? Yes the culture between different races is different but i think the main dividing factor is actually looks..

When Singaporeans look at PRCs or maybe Filipinos, immediate response is, they're a grade below us.. correct me if i'm wrong. When caucasians look at Asians, first thing they think is, they're a grade below us.. When an American looks at a Singaporean, and then at a PRC, well, I don't know who is above who but the American is definitely above singaporean and PRC.