Well, obviously, you want to play as many of the notes as possible, and one should strive for perfection, but how important is it to actually play all of the notes? Is being able to play every note every single time something that important? How many errors are acceptable?
My piano teacher has always accented playing musically, and that the notes are far from the most important part of the piece. Of course, this is coming from a man I've seen play Rachmaninoff's 2nd, a piece I know as well as is possible without having played it, and I didn't hear a single wrong note.
In general, I think it's a good learning strategy to learn pieces beyond one's skill level, but then, how can one be expected to play a piece beyond their skill level and play it flawlessly, from a technical perspective? I can play pieces a bit below my ability without missing any notes, but any piece I would play for a recital would be on the higher end of difficulty for me, and I couldn't play that flawlessly. Is the expectation that one shouldn't even perform a piece until after it becomes "below" what they are capable of?
I get the impression, reading this board, that most people here expect that a performance should have no wrong notes, or at the most, a couple. I'm really interested to hear what people have to say.