According To CoCo Chanel: Guide To A Professional Dress Code

The professional dress code may have changed over the years, but the importance of dressing the part has not. There was a time when I would not walk into federal court or even my office unless I were wearing a suit, stockings, and heels. Now in the age of "business casual" and "anything goes," there tends to be a preference toward casual over business, often resulting in questionable choices.

Appropriate business attire differs by industry and varies widely by company culture, but failing to dress in a manner that is respectful to those around you is always a mistake. Inappropriate attire suggests that you are not a serious professional, or worse, it says to your audience that they are not worthy of your best.