The Three Sieves of Socrates

One day, old Socrates is out walking when all of a sudden a man runs up to him; "Socrates I have to tell you something about your friend…”
“Wait…” Socrates interrupts him; "The story you're about to tell me, did you put it through the three sieves?"

"Three sieves?" The man asks.

“Yes”, Socrates says…
"The first sieve is the sieve of truth, did you examine what you were about to tell me to see if it is true?" Socrates asks.

"Well, no, I just overheard it" The man says.

"Ah, well then you need to use the second sieve, the sieve of good." Socrates asks "Is what you’re about to tell me something good?"

No, on the contrary" the man answers.

“Right;” The wise man says "Let's use the third sieve then, is it necessary to tell me what you're so excited about?"

"No, not necessary" the man says.

"Well" Socrates says with a smile "If the story you're about to tell me isn't true, good, or necessary, just forget it and don't bother me with it."