If you light upon an impertinent talker, that sticks to you like a bur, to the disappointment of your important occasions, deal freely with him, break off the discourse, and pursue your business.

Someone who will not stop talking is not going to release you out of consideration, and waiting politely for a natural gap can cost you the afternoon. The kind thing and the necessary thing here are the same: end the conversation plainly. Most people are less offended by a clear exit than by the resentment that builds while you endure them.

Have a sentence ready and use it early. Say that you need to get back to something, and go, without inventing an elaborate excuse. It feels abrupt once and saves the relationship a great deal of quiet irritation.