This proverb is found in another place, chapter 15:13. There it has a different sense though it is more or less the same proverb, but we should interpret it so that it fits its context.
Do you find yourself avoiding the wholly negative person and turning to speak to somebody else? You see them at a distance; you know what is coming, always a grumble, a complaint. This is about fellowship too. Fellowship knows how to rejoice.