It's a negative creativity.
First you look deep into the mess and pick out what you like; the elegant healthy stems that dominate, the symmetry among groups of stems, the view of what you'd like to see looking through if only it weren't for all that mess.
Then you notice the mess; the crossing branches, the branches pointing inward, dead branches, broken branches, the puny little branches that will never amount to anything - all that visual clutter interfering with what you liked when you first looked into the plant.
Also, you pay attention to the space between the branches you like. You pick the ones that are a pleasing distance from its neighbors - not too close and not too far. Try to keep distances between the branches more or less consistent - to match the natural personality (called "habit") of the species you are working with. You can see the habit in your mind's eye if you look closely at the plant.
Lastly, you cut away all that other stuff which interferes with your vision, focusing on those stems you liked when you looked in the first time. You want to see what's not there and then make it that way by cutting out the mess.
You end up with a plant that appears not to have been pruned at all!
You create it by taking away.
