What is the difference between perfect and excellent?
What is it that you demand from your team - perfection or excellence?
One definition of perfect is "conforming absolutely to the description or definition of an ideal type" . Are you looking for an ideal or something that conforms completely to the described result?
One definition of excellent is "possessing outstanding quality or superior merit; remarkably good".
Are you looking for outstanding, superior results?
I can't answer that for you. You will need to understand what it is that you are requiring your team to do. There may be an instance where 'perfect' is impossible. For example, if it is a very subjective project, perfect could be different in each person's eyes. You may need to settle for outstanding - is that so bad?
Make sure that the team you lead knows the difference between perfect and excellent, including your expectations. It will make execution easier and better!