Guys, professionalism starts from within. It can be taught later in life but ideally should come from a solid upbringing. (Might be a root cause there)

Pilots that walk around looking like crud make me look bad, and that irks the heck out of me. People still look up to us, whether they admit it or not. If a passenger give you a hard time, don't let him. Accepting less than what you deserve is what is bringing this profession down. It goes from passengers, to gate agents, to schedulers, to managers, to flight attendants, to pilots within our ranks. You get respect when you show that you deserve it. How you do that is by showing that you respect yourself.
When you respect yourself, and your profession that bleeds out of your being. With half of the group thinking they are sending a message to the company that a dirty shirt is going to scare the pants off of management they are dead wrong. You wear the uniform and perform the job as flawless as possible because it is what you (singular), and We (the professionals) beleive in. Doing that not just shows the appearance of being a professional, but will command the respect from those you want to be respected by.
It will not make you more money, but it will change the way you see things. Take pride in what you do, because how can you expect anyone else to if you do not?