If you send an important email, text, whatever and do not get a reply for hours you know that at least today that person is not being attentive to work

This might be industry specific, but for me it’s the exact opposite. If I respond to emails or slack messages immediately, it’s probably because I don’t have anything important that I’m working on, or that I’m just browsing Lemmy or something. If it takes me an hour to respond, it’s because I was head-down on something and didn’t want the interruption by changing focus to something different.