I expect a lot of it comes from people not being aware of what Shift+Enter does in Slack. There is a setting in Slack which makes Enter break lines, and Ctrl+En

I expect a lot of it comes from people not being aware of what Shift+Enter does in Slack. There is a setting in Slack which makes Enter break lines, and Ctrl+Enter send the message. IMO it should be the default. It could break away with the habit of standalone hellos and with big messages being broken into 7 smaller ones (each generating a notification, and making it harder to judge when the other person stopped forming their message). Instead, sending a message would be a separate action from composing it. Of course, it's inevitable that some people won't appreciate other's time and attention, but that's probably unsolvable.