Some Ways People Are Mentally Lazy About Judging Others
I think for the most part people are good and mean well, but our minds are wired to think about their fellow humans in ways that aren't always logical. It can be frustrating when you see it happen, but I think it's one of those things you can't really change. Below are some ways people aren't entirely rational when they think of others. If you're familiar with the concept of cognitive biases, you'll recognize some of them below.
Assuming there's nothing that can be done about these tendencies, everyone will choose to deal with them in different ways. One response is to be pragmatic and think "If that's how the world is then I'm going to adapt and do what it takes not to trigger these reactions." Someone else may go, "It's all well and good that people think this way, and sometimes it will hinder me, but I'm going to stay true to myself."
We're overly quick to judge people based on superficial impressions
When we meet new people we can't help but form a snap opinion of them, based largely on surface information. Of course, we often get this first impression wrong. The psychological explanation for this is that we don't have the mental capacity to carefully evaluate each new person we come across. Making an overly quick, and possibly inaccurate, judgment is a shortcut.
We're prone to relying on stereotypes and other rules of thumb
Not only do we size people up too quickly, we often fall back on stereotypes to help us do it. We all do it, even if we're progressive and should know better. It's another shortcut we unconsciously use. The stereotypes can be negative or positive, subtle or exaggerated. We may also use our own more personal rules. For example, if you've had good experiences with a certain type of person, in the future you may automatically like anyone who seems similar.
Our overall impression of someone is sometimes based on a few key traits
Often, if we feel someone has a few key positive traits, we'll see them positively on the whole. This halo effect is often mentioned in regards to attractiveness. If someone is good looking, we're more likely to think they're also smart, confident, fun, and so on. Similarly, if we see someone as having a key undesirable trait or two (also attractiveness possibly), then our overall impression of them will be more negative.
Once we've made up our mind about someone, it's hard to change our opinion
First impressions are strong, but they aren't everything. People do sometimes admit they were initially wrong about someone. It is harder than it has to be for people to come around like this though. Once we've formed a belief, a confirmation bias can kick in where we look for information that supports existing our views, and selectively ignore that which doesn't. If someone has decided you're shy and uptight, they may not notice all the times you are friendly and outgoing but seem to pounce on the times you are a little reserved or anal retentive.
We sometimes create self-fulfilling prophecies to cause people to act like how we expect them to
The way self-fulfilling prophecies work is that when we think someone will act a certain way, we sometimes unintentionally change our behaviors to elicit the very actions in the other person we expect. The classic example is if you think someone is a snob, when you run into them you'll act unfriendly and aloof. Naturally, they'll be offended and snub you in return. Then you can go, "See, I knew it. They snubbed me." A more positive example is expecting someone to be friendly and then being really open and bubbly yourself. When they see you and your sunny disposition, odds are they'll be just as affable as you thought they would be.
More on this here: Self-Fulfilling Prophecies In Social Situations
When we judge other people we often give a lot of weight to the social impression they make
The points above feed into this one. When we form an overall opinion of someone, we base it on a lot of factors. I've noticed that we often give too much weight to how someone comes across socially. This impression is largely quick and superficial, and is based on what people say, as well as their non-verbals, like their tone of voice, how they dress and groom, and their overall appearance. If someone comes off as well put together, likable, and socially polished, people will tend to see them positively. (Note that I mean this applies if they genuinely come off well, not if they're overly slick or falsely chummy, which really is a knock against them in most cases.)
If someone's social skills are bad then everything they do gets tainted by association. If a personable, regular guy says he likes a stereotypically dorky interest, like science fiction, then people will probably say something like, "Oh yeah, really interesting." If an awkward, disheveled guy says the same thing, the people will respond with, "Ugh, he's so obsessive. He needs to live in the real world." The actual interest carries no weight, we respond to the person who's doing it.
The practical application of this point is pretty easy to guess. I say something similar at the end of this article. If you have good social skills, look half decent, and generally don't set off a bunch of negative stereotypes in people's minds, then you gain a lot more freedom to do what you want.
Good social skills are always an advantage, but you can only go so far with changing your appearance as to not set off stereotypes. No matter what group you fall into, it will have some negative associations. You can't win with everyone. So if something about your appearance is central to your identity or subculture, then don't change it.
On the other hand, if you don't care much about something either way, then you may decide to go the pragmatic route and do what makes you come across better. Like you may decide it doesn't really cost you much to try out a new haircut, or get contact lenses or a nicer pair of glasses. It may then make your life go more smoothly when people stop instantly assuming you're a nebbish engineering student.
We often care more about how well we get along with people than other factors
This point is the bane of highly competent but mildly prickly employees everywhere. In some situations we should logically be judging people primarily on issues like how skilled, productive, intelligent, or creative they are. But we don't. We seem to reward the people who are easy to get along with. Their more talented, but difficult to get along with, peers are held back.
It's not that simple, of course. "Soft skills" do matter. We have to be able to properly communicate with each other. Lots of workers just don't care about their jobs that much either, and would much prefer to pass their days with a fun, mediocre colleague over an uptight effective one. Also, talent and social skills aren't always an either-or thing. Still, it seems sometimes the most rational, beneficial thing to do would be to reward people purely based on merit, and forget about all the softer stuff. We usually let our social judgments get in the way. The idea of letting someone unlikable get a free pass can seem wrong to us.
We tend to judge people mainly based on how they treat us, and are sometimes too quick to overlook how they treat others
This point discusses a more ugly side of human nature than the others. In general, if someone is a jerk to other people, but nice to us, we tend not to be as upset with their dickish behavior as we should be. They treat us well, and we can't help but put more importance on ourselves. Also, we feel how we're treated in an immediate emotional way. We tend to think of others in a more abstract, detached sense.
This is all within reason of course. If someone beats up our little brother, or yells at our niece, we're going to be mad. But if our good buddy makes fun of some people we barely know, we can only be so annoyed. There's often more to it than that. We may be too scared of a jerk to say anything, or he may be picking on people we don't care about at all. Still, I think this effect is there, though I wouldn't complain if it turned out I was wrong about this one.