My only concern is that this line of thought can be used as an excuse to stop trying. As long as we agree that one should strive for perfection given the constraints at hand (money / time / problem difficulty / experience level etc) I dont have any objection about the idea.
On a related note, I feel another analogous statement that I now see used dangerously is "Premature optimization is the root of all evil". Yes optimizing prematurely can be paralyzing but the other extreme where one refuses to do back of the envelope calculations and wilfully writes code that will be slow is damaging as well.
I can appreciate that. I have some perfectionist tendencies myself. I think it is a tricky balance that must we must walk. I like your idea of "as perfect as our constraints allow".
Another important consideration is the level at which the quality exceeds the needs of current and future users of the software. Past this point (which might be impossible to determine or fully agree upon), one must acknowledge they continue to iterate and polish for purely personal reasons. This can be fine in certain situations, but it may be a detriment in professional endeavors.
And of course, like always, one must consider opportunity costs.
That's a good attitude to aspire to, but, in real software development, very little code survives contact with users unscathed. If you're writing a C compiler or something with a well-defined spec, then, sure, you can theoretically write perfect software. But, even your basic CRUD web site is unlikely to ever reach "perfect" status.
Edit: For example, the HN code was obviously not "perfect," since we just got several new features. :)
On a related note, I feel another analogous statement that I now see used dangerously is "Premature optimization is the root of all evil". Yes optimizing prematurely can be paralyzing but the other extreme where one refuses to do back of the envelope calculations and wilfully writes code that will be slow is damaging as well.