I can't say I agree, MTPW.
Because many businesses exist to sell something - a product or a service.
They hire employees to represent them and attract customers.
When I buy a service, I prefer a person to be dressed appropriately and/or practice proper hygeine.
I don't want to go to a dentist with black teeth and smelly breath, or have a doctor who reeks of BO and fag smoke lecturing me on how to look after my health and examining me or my children.
I wouldn't hire a personal trainer who's obese.
So I guess I'm shallow then.
But IMO respect and courtesy is a two-way street. And it starts with yourself.
If you don't take care of yourself, well, then, it goes to follow this image that you present will be what potential employers see about you, and if you can't take care of yourself even, then how are you supposed to take care of your employer's interest (which is what they're hiring you for)?