If you do much emailing, you undoubtedly have communicated with someone who must reply to everything. Every message you send gets at least a response of “thank you.”
If you say “thank you”, he says “you’re welcome.”
If you say, “you’re welcome,” she says, “I appreciate that,” or something else equally polite and meaningless.
So, you just have to let that kind of people have the last word. But if you can’t, stand it, you could try saying something like “Gotta go to a meeting. Talk later.” But of course, you are likely to find an email when you return, saying “OK.” And so you have been defeated.
Then are those who insist on having a reply from you. If you don’t acknowledge his email (even when an acknowledgement is not needed) you will eventually get another one asking whether you received the first. When you reply, the email tag can begin.
Then, there is the serial texter. Such people are apparently unable to sit still without sending a continuous stream of text messages — whether you reply or not. As a lawyer, I am concerned about clients sending me text messages with confidential information, so I tell them never to text me. That usually works, at least for a while.
A variation is the serial tweeter. Such a person tweets a stream of comments to all her followers during her favorite television show. Others comment on sporting events, including regular reports on the score. There is a cure for this, of course. Unfollow the tweeter and the unwanted tweets disappear.