I've found the advice to remember that you "only ever actually be doing one thing" not to be very broadly applicable. It's good advice for some situations like driving a car, but for things like writing code while responding to the occasional Slack message, it's not specific enough to constitute good advice.
Still, it's true, when understood properly, and maybe I just need to study it more to put it into practice.
When I'm on call, I've got to respond to slack messages in 4 different channels with a 1hour slo . Messages responded to outside the SLO get brought up at perf review. This isn't viable for some of us.
Still, it's true, when understood properly, and maybe I just need to study it more to put it into practice.