"Why do you see the speck in your brother’s eye, but fail to see the beam of wood in your own?"
   
-Matthew 7:3

This is both stupid and idiotic.  Do not notice, really? This is like saying do not notice the musician is out of tune, or off tempo screwing up the song if you can not play an instrument better, or you suck worse at something.

I see no practical way to practice this supposed "wisdom" revelation from the bible.

Do not notice the black head on someone if you are having a problem with acne

...Pitifully useless advise