Slack has a feature available to workspace admins that lets you suppress the messages that users normally see when people join and leave public channels. (Technically, the feature lets you show those messages, but I believe it defaults to being on.) I think you should disable these messages for all the Slack workspaces you manage, and I shall now take a moment to tell you how and why.

To find and change this setting, select Settings & administration > Workspace settings from your workspace’s main pull-down menu. In the Settings tab of the resulting web page, scroll down to Channel Join & Leave Messages, and hit the Expand button. Finally, if the Show a message when people join or leave channels checkbox is checked, un-check it and then hit the green Save button.

I find the default behavior of this feature well-meaning but subtly harmful. In theory, it makes sense to know when people join a conversation, or when they’ve moved their attention along to other topics. But this, I believe, over-applies physical-world thinking onto the different assumptions of purely online spaces.

While an automatic join-message does have marginal utility, letting others in the channel greet the newcomer without requiring any further introduction, I see only drawbacks in automatically announcing departures. People should have the ability to quietly slip away from a conversation. By instead making every departure conspicuous, a person leaving a channel will at best cause a reaction among those they left behind of quiet surprise and momentary confusion. Some will feel mildly hurt, wondering if the person felt unwelcome, and whether they may have accidentally played a hand in that. Should they reach out and apologize? Is that assuming too much? It becomes a source of small and unwelcome anxiety.

The nadir of this phenomenon happens during more intense conversations, when emotions may run a little higher than normal. This tension happens naturally from time to time in any space populated by people who care passionately about some topic, whether professional or hobbyist. It presents a time when all participants need to navigate carefully to keep things cool. In these situations, a computerized voice butting in to announce a departure resonates like a slamming door.

Too many times I’ve seen an automated message turn up an already heated conversation’s intensity by whole degrees, all by itself. No matter what reason the person had for exiting—maybe they need a quiet breather, maybe they just don’t feel invested in the topic at hand—it becomes far too easy for everyone else to imagine them leaving in an angry, disgusted huff. People already upset can even overtly weaponize these messages: “Now look what you did, you’ve driven off [So-and-so]! I hope you’re satisfied.”

The presence of automated departure messages carry an equally harmful second-order effect for those aware of these problems. If I know that my leaving a channel will likely be seen by others as a noisy storming-out, I will probably choose to stay so as not to make a tense situation worse. And that feels miserable! The best I can do for my own mental health is to put that channel on mute, which often seems disingenuous to everyone else involved, and still keeps a conversation I no longer wish to see just one click away.

Deactivating this Slack misfeature removes this entire bind, freeing people to leave public channels with fewer hurt feelings. While it also gives newcomers the burden of manually introducing themselves (or being introduced), this feels like a small price for the vast relief brought about by changing this setting.

Help keep your Slack workspaces cooler, calmer, and better ventilated. Please turn off your join & leave messages.