Occasionally "good enough" is "as good as it gets." Time restraints may not permit higher quality and you are forced to produce the best possible work under the circumstances.
If you had another year, you might (note the "might") produce an excellent result but you don't have that time and so you do your best, once again under the circumstances.
Now it is important, of course, for the customer to know what is sacrificed in the interests of quicker results but in many cases, good right now beats best but later. Slowing things down to achieve higher quality would be viewed as inferior performance.
Aim for your best but don't forget the circumstances.