> If a person can't work because of a pending question, it usually means they don't have their work organised sufficiently.

This is an overly harsh assumption. There are plenty of compelling real-world examples of organized, effective people being blocked by some small but urgent thing that's not their fault and requires a few minutes of attention from someone else.

If a dev just started on my project but the DB credentials I gave him aren't working (or whatever), that's on me. If my boss's boss jogs over to our office area asking who here knows Thing_X the best, I'm going to deign to remove my noise-cancelling headphones and accept the deep-work disruption.

True, I'm a bit harsh on this, but I also used the word usually instead of always on purpose. Yes, sometimes someone can really get blocked and not able to work, no problem to ask for help in this case. On the other hand I have seen it enough times that people (especially juniors and bosses) continuously ask question without having bothered to think about it prior. Forcing them to deal with a problem by themselves for a bit and not distract others has resolved many of them.

The key thing is being clear what communication and team culture you want to establish. I'm not just a grumpy guy that ignores messages or avoid helping others. It is something that has been discussed and agreed upon in the company and is expected to be respected by anyone no matter where the person is in the hierarchy.

Fair enough: I agree that plenty of people prematurely ask someone rather than try to figure out a solution by searching, thinking, experimenting, etc., and using Slack as an asynchronous channel will generally encourage people to hack a bit more at their problem before instinctively distracting the person next to them.

Yep, this is exactly how I use it at my office. Slack isn't where 'deep work' happens, it's one of the things that allows me to accomplish 'deep work' by reducing interruption and distraction.

Exactly. Take pride in being that person who is so busy/focused that you can't be bothered to respond instantly to every discussion. Slowly train others to understand this working style.