It takes just a quick glance, maybe three seconds, for someone to evaluate you when you meet for the first time. In this short time, the other person forms an opinion about you based on your appearance, your body language, your demeanor, your mannerisms, and how you are dressed.
With every new encounter, you are evaluated and yet another person's impression of you is formed. These first impressions can be nearly impossible to reverse or undo, making those first encounters extremely important, for they set the tone for all the relationships that follow.
So, whether they are in your career or social life, it's important to know how to create a good first impression. And like it or not, they are going to form their initial impression of you based off of how you look.