"A fool thinks himself to be wise, but a wise man knows himself to be a fool. "
Shakespeare
http://www.youtube.com/watch?v=MvxhyKpNYD8&feature=related
http://www.youtube.com/watch?v=wCQBbgb_Lvo
http://www.youtube.com/watch?v=N9i2fqxSjTI&feature=related
http://www.youtube.com/watch?v=xtqy4DTHGqg&NR=1