Creative Tension

I am just unloading the kiln . Wow. Magic. Here I am at the very last shelf. This is the second and most important firing. The high temperature  melts the glaze, and voila,  the finished product! The turquoise color is just what I wanted. No obvious cracks or runs. It is a good firing. 
I never quite know how things are going to turn out. Did I mix the glaze to the proper consistency? Are there any weak spots that are going to crack? Is the atmosphere in the kiln going to give me that certain glow in the color I am aiming for? Will the kiln gods smile down on me that day?
You would think after all these years I could be sure of the outcome. However, there are so many variables in high fire ceramics. It is never a sure thing, until  the shelves are emptied. Two months of  my hard work, and I do not know the outcome until the last unveiling. 
An artist friend often speaks about the tension involved in the creative process. That tightness in your stomach as you attempt to reach whatever mountain top of creativity you are climbing. The uncertainty of outcomes, as you spend so many hours working. 
It is just that part of what we go through, striving to do our very best.