WHAT MAKES US, US?

We all claim to be so different and so unique, but when you really think about it, what makes us all so different? What do we judge each other on?
Do we judge our peers on what we think when we first see someone?
What clothes they wear?
What's happened in their past?
What they dream will happen in their future?
Who's the smartest?
Who's the most popular?

Do we judge people in reference to the world around us, or in reference to what we actually know of that person?

This is the real dilemma in my mind right now. We all judge some people to a certain degree, but what do we really base those judgments on? I don't know if we judge someone on what we know they have done in their past, who they are when they're with us, or what they're like compared to everybody else in the room.

In one situation, someone could rule the world, hypothetically of course, while in another, be a total outcast. Do we judge people based on who's friends with who? Who's the nicest person underneath all of the random bull that is in the world?
For example, when you look at me, how do you judge me? Do you look at me and hear all of the random things (some true, some false) that people say about me, or do you take the time to come to your own conclusions?Do you decide whether or not you're going to talk to be based on what I wear? Do you base me on looks compared to everyone around me? How do people get the stereotypes they do? I know that everybody makes judgments every single day, but what are the things that cause a person to fall into one, rather than the other?