Bert, I think it is apples vs. oranges. My belief is that Sharon Stone was talking was very much in the context of acting. I think she was speaking about getting in touch with the not-so-good side of ourselves in order to act out the part of that kind of character. The ability to do that can set one apart from other actors.

Now, if one wants to attempt to apply that to the "all the world is a stage" idea, I think it falls apart. But if you can use it in your art, whether it be painting, acting, singing, or whatever, you can bring a uniqueness to your performance.

Let's say you are singing "John Hardy". By some accounts, John wrote this while the gallows were being built with which to hang him for murder. One could sing it with the feeling of being a braggart or with that of one who was truly contrite for what he had done. I think that being in touch with either of those feelings could very much enhance one's performance of the song. There are probably better examples; but this one came to mind.