However, men are not perfect in any aspect of their lives, no matter the amount of time, effort, and energy they put into their search for perfection. The virtue of perfection is that it is always just beyond a man’s reach.  This is good. If perfection were attainable then it would have no value - there would be no reason to pursue it. In this light, always know the strengths and weaknesses of yourself and your enemy. 

Miyamoto Musashi - Book of five rings