Psychologists say that most people form impressions of others in the first four minutes and that 80 percent of an impression is based on nonverbal signs. In other words, what comes out of your mouth has very little to do with how people judge you. Also, after you make a first impression, getting people to change that judgment is hard.
How you dress, how you groom yourself, and how you handle your body language in the workplace are all part of your "packaging." As in product packaging, you can present yourself to be most appealing, and you can present yourself differently according to the time and place.
A well-mannered person always considers the impression communicated by clothing, body language, and grooming. Always be thinking about what your appearance says about you. Never pretend to be anything you aren't. You should not be uncomfortable or present an image that is not you, but you should present the best you that you possibly can.