If you surrender your self-worth to someone who doesn't see your true value, what happens when someone comes along who wants to give you what you're worth instead of what you'll settle for? The bottom line is this: You've got to know your worth, at yard sales and in life, because a lot of people who are going to try to talk you out of it. If they can't see your value, let 'em keep on movin'! Someone out there is looking for exactly what you've got and will never try and undercut your value or question your worth. Some things in life just can't be bartered over or placed on the sale rack, and your self-worth is at the top of the list.
It is a matter of artistic instinct. In his own thoughts and feelings and way of doing things an actor is worth nothing or he is worth something. If he is worth something then he will try to be worth something more as is only normal in anyone who wants to get on. I can think of no other way to explain artistic development.