There are several places of sucess when you are creating art, how do you decide which one is where you want to stop and call it finished?

I was recently introducing several young women to pastel.  Nothing gives you a newer perspective than seeing your medium from the perspective of youth and this was eye opening.  All of these girls were eager to get into the medium and while they were shy, several took charge of their pieces and took them in directions that I had never thought of.  I was impressed and amazed by their courage but there is always one, who has an inner vision and fights to make their piece match it.

All of us artists fight with that.  We know how we want it to look, we each try to take our work to that point but sometimes it takes us places we weren't expecting to go.  I remember working on a painting during an artshow one year and the artist next to me kept telling me to stop.  As I progressed, she kept telling me that I had created several paintings with that one already.  It became a wonderful piece in the end, but I never forgot how she kept exclaiming that I could have stopped at anyone point to have a finished work.  

It wasn't that I overworked it, from her perspective; it was successful everytime she looked at it.  I wished that I could have helped my young student to see what she was accomplishing like this artist was able to point out to me.  The other girls in the class could see it, but because of this young artist's emotional investment in the final image in her mind; she couldn't see her success.

Sometimes we get so focused on our final goals, we loose sight of our accomplishments on our journey to reach them.  As creative person, learning when something is finished is one of the hardest lessons to grasp.  At what point are we making a conscious decision to go beyond the finished image in front of us and work towards another goal with it.  What makes us decide to stop when it is more abstract, rather than push ahead to our mental goal? To some, it is a matter of courage.  Letting your piece stand alone outside of the other works that you have done.  It doesn't match your body of work, is that a bad thing?

I hope to see her again soon so that I can have the chance to explain to her what I see when I look at her and her work.  Hopefully, if I don't get the chance; someone else will be able to explain it to her.  I'm going to include a photo of my work in process to see what your opinions will be.  Be honest but forthright.  Thanks.