[misterremote]

You put this very nicely, thanks. There are different ways of doing things for the different purposes.

This reminds me the time I was working at the office. We had an open floor plan, and so no doors (except the CEO).

It was sometimes nice to talk to people, but there were times when I was deeply in code, and someone asked a small random question from me. It was clearly because he/she wanted just to talk. This would have been better to ask through Slack as I could then continue my work and answer later.

So what I usually did was a) stayed home for deep work hours or b) put on my headset and listened to music to indicate that my "door" was closed.

And yes, with the CTO the physical door was an indication: if it was open, we went in and discussed something, and he was always happy to do so. When it was closed, we didn't interrupt him, and when we did, you could feel that he was feeling indeed interrupted.