I read it, you said a few days ago in a rant of yours iirc and I couldn´t agree more. I heard this very same phrase - or at least the bottom line of it - a few months ago in a series, it went something like "sometimes you can play at your best level and make no mistakes, and you are still going to lose the game".
Exactly, our parents told us to aim for the stars and well, sometimes aiming that high will only bring disappointment. Not everyone can reach the stars - otherwise they wouldn´t be a goal. Yes, we have to be ambitious but also we have to be realists.