I don't like the "good enough" mindset. In my work, I understand that I will never reach perfection, but that doesn't mean I shouldn't try my best to strive for excellence with the given circumstances.

Of course, there is always a balance / trade off between quality of work and time spent. My strategy is to have a set of requirements for my work and every requirement must be met before it becomes acceptable, or else it must be worked on again. Also, I have a rule of thumb, which is "if I can see something wrong with the work, the customer can see it too." So if I see something wrong with my work, I will take it completely apart and work on it again if I catch something wrong with it. Better to fix my own problems on my own than have the customer point out my fault, while still having to fix it later.