I believe there is no such thing as 100% satisfaction in prosthetics — not that perfection is impossible, but that we never settle for a result and keep looking for anything that could be better.
Even when treatment has gone well, I take one more look for anything that could give the patient a better result.
One case I remember is the upper front teeth of a patient in her forties. Beyond the change in her teeth, she became noticeably more active in taking care of her appearance. That was when I felt that dental treatment can reach beyond the teeth into a patient's daily life.
That is why I value the process of looking and thinking once more, right to the end, instead of settling early.