" The yogis say you can never step into the same river twice, because the current is always shifting and changing. You've never stepped into this exact river before today. Not with this body, not with today's particular energy, with the specific number of bites of breakfast in your belly, with the earth tipped on its axis. Perhaps up until now you haven't had a breakthrough in this pose, but that was then. What's possible today? "

― , Perfectly Imperfect: The Art and Soul of Yoga Practice