the practice of perfection

One blog I follow is written by Brooks Jensen, from Lenswork, offering a variety of technical information, random musings, and discussions of portfolios.  There was this in one of the entries today -

"That said, let me also reiterate that there is a flaw in the often quoted, 'Practice makes perfect.' I think it was some concert pianist who suggested the improved quote, 'It is the practice of perfection that makes perfect.'"

And isn't that what can be so frustrating about photography, or anything else we pursue with passion?  The elusiveness of that perfection?  At the same time, isn't that what keeps us going at it?  His bigger point is that practice - to be beneficial - must be deliberate, purposeful.  f8 and be there was never enough.  A beginning, perhaps, but never enough.