Whether it is haiku or not, it is 17 syllables, and a good addition to the Stoic's armamentarium:
Avoid the near occasion
Of unnecessary conversation.
Avoiding the near occasion is not always practicable or even reasonable, but pointless conversation itself is best avoided if one values one's peace of mind. For according to an aphorism of mine:
Peace of mind is sometimes best preserved by refraining from giving others a piece of one's mind.
The other day a lady asked me if I had watched the Republican debate. I said I had. She then asked me what I had thought of it. I told her, "I don't talk politics with people I don't know extremely well." To which her response was that she is not the combative type. She followed that with a comment to the effect that while in a medico's waiting room recently she amused herself by listening to some men talking politics, men she described as 'bigots.'
I then knew what I had earlier surmised: she was a liberal. I congratulated myself on my self-restraint. At that point I excused myself and wished her a good day.
Companion post: Safe Speech. "No man speaketh safely but he that is glad to hold his peace. " (Thomas à Kempis, The Imitation of Christ, Chapter XX.)