I believe art to be a collaboration of forces in the Universe so I try not to have a vision set in stone when I create a piece.  It's kind of like working with a team of artists of which I'm only one part of the whole; maybe an important part, but nonetheless just a part.  Yes, the vision must be strong enough to convey to my other (unseen) team members, but not so rigid that I reject or ignore their contributions.  When I hold my vision and remain open, they always come up with ideas that, many times, take the project in a direction I could not have even imagined.  This delights me as I'm always pleasantly surprised by the end result and left with the feeling that I'm not too sure who actually created it!    

Lesson:   The more I practice flexibility, the more room the forces of the universe have to shape the the spirit and outcome of my work.