To judge is our conclusion of the unknown.
Judgment is not based so much on the perception of what we see, but more on what we feel about what we see. If we judge with our emotions, we can't be impartial, but if we choose to be open-minded, then we tend not to judge.
When we find ourselves in front of someone, it's the tip of an iceberg standing in front of us, and lurking deep down in the waters, the iceberg is unknown to us. Each person comes with baggage of experiences that made that person who he/she is.
If we don't know the content of this baggage, our judgment is distorted. When we see someone and are ready to judge, we should always remind ourselves of the hidden truth - the past and the experience of the life of that person.
It exists a myth that says always to trust your first impression. I disagree. People have a facade up most of the time. A person can be on her best behavior, and in reality, it's not good to be around that person. Or conversely, it could be someone that looks like she has rough edges, but actually, she has been through a lot in her life, and she is the most lovable person ever. I believe that we have to get to know a person instead of judging on first sight. Knowing what lies beneath might make us either avoid trouble or not missing out on a great friendship. Also, it can change the course of our behavior toward that person and toward judging. For example, it may happen to be that we can be the ones to help or defend that person against a judgment, which is a better disposition to be in than to be the judge.
We have to have empathy to be able not to judge, and the best way to achieve this is to take the time to listen, feel and put ourselves in the person's shoes while asking ourselves if we had done better in that person's place. If we pretend that we would/could have done better, it's clear that we lack empathy and our pride took over.
The perception of what we see or hear triggers an emotional reaction. Different feelings push us to judge. It can be anger, disgust, bitterness, envy, jealousy or pride, to name some. When we judge, it's often a reflection of the state of our own heart, which in turn cannot be externally judged since we too have a baggage and experience of life. But we can ask one question here—how can I restore myself to be able not to judge others? The answer to this issue is to do some honest introspection and fix the problem at the source.
To negatively judge someone is in some cases putting ourselves above the other. Or, it may be that we are insecure, afraid or intimidated by that person. Either way, none of it's justified. We have to be open-minded about differences of worldview, culture or faith, and the particular ways we visualize according to our self-approved standards. To be open-minded allows us to have understanding and compassion instead of passing quick judgments or condemnations.
We also may tend to judge behind the person's back, gossiping about what we think. Why? Do we believe that we are better than that individual? Who are we to take such responsibility to be the judge of someone when they are not even present to defend themselves? Don't forget that the person to whom you are gossiping to, may judge you for doing so. People are not senseless, they know that if you gossip in someone's back, you will do it to them, no doubt about it. Your judgment of other defines more who you are than your gossip about the individual.
If we are conscious that were created to be kind and loving toward our neighbor, we should not be proud of judging. At the moment, we can feel good for boosting our ego, but when we find ourselves alone with our conscience, we can't feel good about judging, unless we lie to ourselves to justify our wrong doing.
Shamefully, I had to go through harsh judgment myself from others to be able to understand that I shouldn't judge anybody and to realize how fast and easy is to judge.
All people judge others for one reason or another, and we judge all the time as good a person as we might be. We are so accustomed to doing so, that it's second nature. We may not even realize that we are doing it most of the time. But the day we can see that judging is an unwise and unkind habit, deciding that we want to stop judging, we then are facing a mountain of work on ourselves to become free of judging. It's a life's work of fighting impulse and awareness of what sometimes comes out of our mouth, but worth it. In all, awareness is the key to the beginning of healing.
Conclusion, we should not judge as we wouldn't like to be judged.