I believe we judge people to much because of their appearances. For example, people who say they fancy someone a minute after they have seen the person are stupid, as that person could be a criminal or just disrespectful and they would not know it as they have never met the guy.
Of course people are going to judge others right away on appearance. If I see a person with really raggy clothes on, I think that either it's one of those 'I hate everything' days, or they might not have enough money to buy new clothes. I'm not saying that judging people by appearances is right, but I think our minds are just set to judge people like that.
Without biases, we aren't able to survive at all- we would bump into things, get lost in our own homes, etc. But of course biases is bad in this case.
People in fact often judge the personality of people by looking at their appearance. This is called stereotyping. Although there really is correlation between appearance and personality, it is only to a certain extent and often inaccurate in real life. Most of the time, coining people with stereotypes is self-fulling sadly. For example, you reckon a person as someone who don't really like to be with people just by judging his nerdy or unattractive or drowsy appearance. So you avoid him or when you finally need to talk to him, you talk to him in a way or tone(unenthusiastic perhaps) as if that person really don't really like you, which doesn't sound friendly to that person at all. Guess in what manner would the person talk back to you? The same probably. And you would think: oh he really is like that.
There are so many bad stereotyping based on wrong assumptions thanks to the media. How do the most heroic, kind, courageous people look like in TV dramas and movies??