Recently I had a friend tell me that they thought I was "deceptively intelligent." I laughed at this and made a comment that it probably had to do with the stigma that blondes aren't smart. If you judge someone based on their appearance or a stereotype, you'll be surprised once you get to know them and realize they aren't at all how you originally perceived them to be.
Just like the expression, "Don't judge a book by its cover," a glance at someone's outward appearance does little justice to who they really are and what they've been through. For some reason, we as human beings have a tendency to observe someone and think we know what kind of a person they are. We automatically assume we know their story. Whether it be based on their clothes, their ethnicity, the way they speak, etc., we decide we know more about a person than possible, based on shallow, preconceived ideas that we have been taught or have learned from others around us.
The more people I get to know, the more I understand how much deeper our human identity extends beyond the outward appearance. We all have a desire to learn, to progress and to improve. Every single person has unique life experiences that shape them into who they are. When we judge someone based on a glance, we create our own idea of their life story.
It is impossible to know and understand someone completely because you haven't lived their life, been through the same struggles, or experienced their emotions in the same exact way. We try to pretend we understand, but there is no way we fully can. So we fill in the gaps, pretend we know more than we do, and often in the process completely misinterpret a person.
You might think you have a shallow idea of who someone is and then be surprised, once you know them better, when they don't fit into the mold you created for them. The thing about stereotyping is that it tries to simplify human beings, take away their individuality, and place a label on them. Maybe there is some truth behind the stereotype you attach to a person, but I guarantee no one will fulfill your "idea" of who they are to a "T." Not all blondes are unintelligent; not all Muslims are terrorists; not all Americans are overweight; and not all Latinos are poor.
When you slap a label on a person based on their ethnicity, appearance, clothing, etc., you are stripping away the very thing that makes them human -- individuality. There is a lot more to a person that what you see. Get to know someone better and you will find your first impression is almost never accurate.