People are so grumpy. If you don't want notifications turn them off. If I approach you in person I don't say hi and spill out a paragraph. So saying hello to start a conversation is a low friction way to have a conversation in the same we humans do in real life.
edit: Are people really so unfriendly and impersonable that a simple hello is considered offensive? For the same reason I disable most mobile apps notifications on my phone, you can do same with instant messaging. Stop blaming other people's personalities.
I'm regularly on a support rota as first-line triage for things which have just started going wrong. I need to be interrupted for important things, but I would strongly prefer not to be interrupted for unimportant things, because undivided attention is very scarce on such a rota; doubling the number of messages while we perform the SYN-ACK dance doubles the number of interruptions. Setting my status to "does not receive notifications" forces everyone to read my personal how-to-interact-with-me user manual to discover whether I'm temporarily muted for some good reason, whether I just happen to be away from my desk and would prefer not to be interrupted but can easily come back if required, or whether I'm muted on general principles.
> If I approach you in person, I don't say hi and spill out a paragraph.
I don't know how you interact with shopkeepers or other such people who are there to help you, but I certainly do precisely that; I would consider it rather odd to start such a conversation with a "hi" that waits for a response. Surely, surely, the natural thing to say is "Hi, I'm looking for these shoes in size 10", rather than "Hi". Surely?
I feel like this is supposed to be an insult, but I really don't know what the difference is between "someone wants me to do something for them" and "someone wants me to do something for them in a shop". There are plenty of opportunities for socialising that aren't "when everyone is trying to get stuff done".
edit: Are people really so unfriendly and impersonable that a simple hello is considered offensive? For the same reason I disable most mobile apps notifications on my phone, you can do same with instant messaging. Stop blaming other people's personalities.