Some Ways People Are Mentally Lazy About Judging Others
I believe for the most part people are good and mean well, but our minds are wired to think about each other 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 totally change. Below are a few of the congitive biases people can have when sizing someone up.
Assuming there's not much that can be done about these human tendencies, everyone will choose to deal with that in their own way. 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 those reactions." Someone else may go, "I know people think this way, and sometimes it will hinder me, but still 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, like what they're wearing or how they shake our hand. Of course, we sometimes get this first impression wrong. The psychological explanation for why we're like 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, assessment 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're all prone to this, 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 feel friendly toward anyone who seems similar.
Our overall impression of someone is sometimes based on a few key traits
Often, if we believe someone has a few key positive traits, we'll see them positively on the whole. This halo effect is often mentioned in regards to physical attractiveness. If someone is good looking, we're more likely to mistakenly assume they're also smart, confident, charming, fun, and so on. Similarly, if we see someone as having a key undesirable trait or two, then our overall impression of them will be more negative (e.g., "They dress badly. They must also be awkward, poor, lazy, etc.")
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 our existing view, and selectively ignores that which doesn't. If someone has decided you're shy and uptight, they may not notice all the times you're friendly and outgoing, but seem to pounce on the moments you're a little reserved or fussy.
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 behavior to elicit what we expect from them. 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. Look at how they just brushed me off." 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. We often give too much weight to how they come 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, body language, and how they dress and groom. If someone comes off as well put together, likable, and socially polished, people tend to see them positively. (This is assuming they genuinely come off well, not that they're overly-slick or falsely chummy, which 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 think something like, "Oh yeah, those stories are really interesting." If an awkward, disheveled guy says the same thing, the same people can respond with, "Ugh, he's so obsessive. He needs to live in the real world." The actual interest carries little weight. We respond to the person who has it.
The practical application of this point is pretty easy to guess. 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. I say something similar at the end of this article.
Good social skills are always an advantage, but you can only go so far with changing your appearance to not set off stereotypes. No matter what group you fall into, it will have some negative associations. You can't win with everyone. A suit that impresses people in a boardroom can make you seem like an out-of-touch square in another setting. 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 an aspect of your style 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 a nicer pair of glasses. It may 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 judge people primarily on factors like how skilled, productive, intelligent, or creative they are. But we don't. We reward the ones who are easy to get along with. Their more talented, but abrasive, 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 toxic 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 only applies to a point. If someone beats up our little brother, or is disgustingly disrespectful to a friend, we're going to be angry. But if our good buddy makes fun of some classmates we barely know, we can only be so annoyed. There's often more to it than that. We may be too scared of a bully to say anything, or they may be picking on people we don't care about at all. Still, I think this bias exists, though I wouldn't complain if it turned out I was wrong on this point.