We're always told, 'Don't judge a book by its cover', but that doesn't deter people from judging people based on how they look anyway. This sales rep made the mistake of her life when she refused a casually dressed customer service. OP was walking by a designer store when she noticed a cool backpack that caught her eye. She went inside and asked one of the employees if she could bring it out so that she could take a closer look before purchasing it. The sales rep basically scoffed at her and to…