You don't have the context of the entire business, and sometimes they have an actual need to interrupt you, and you need to stop what you're doing.

In my experience the vast majority of people are reasonable, especially in a professional environment.

>> If you ask them if that will work, they'll tell you they need the answer immediately most of the time.

The question "Will that work" is optional. You need to be polite when dismissing someone, but the goal here is to offer 2 messages "I'm busy now" and "I'll get to you as soon as this busyness passes" The discussion needs to end as quickly as possible so as to not lose your focus, but also without making them angry. Asking questions in that case is probably a bad idea.

I just close the door.

The few times in my career when I haven't had a door I could close, I did all of my deep work from home and only came into the office for meetings (which I compressed into 1-2 days).

The delicate social dynamics described in these threads sound incredibly expensive. I can't imagine paying someone a quarter or half million dollars and then draining away their productivity on this sort of thing.

I got so tired of defending my time at a previous job that I just started saying “Is that what our producers needs me to do?” Shuts them up every time. Generally, the people that interrupted me were people that had no authority to ask me to do anything: marketers, ad agents, sales.

I just instruct my guys to say "I have to prioritize what I'm doing right now. Go talk to HeyLaughingBoy if you need me to work on something else."

They have no problem doing that. Do it often enough and the people learn to just come straight to me instead.

I can't even imagine the hell of working with someone who responds to every request with "Is that what $THIRD_PARTY needs me to do?"

Then you’d be the kind of person I’d say this to. I am very open and accommodating for individuals on my project that are trying to get their task done. I’ll sit down and help, guide, whatever is needed. I won’t allow a marketer, ad agent, or sales person to demand that I stop everything I’m doing and address the issue they have, only to tell them that it isn’t going to be done this sprint and you’ll have to talk to our producer to get that task.

The only people that I’ve worked with that were intrusive, pushy, and demanding of engineers immediate time were the people that were trying to go around the producer because they already knew their issue was low priority for the team.

That is exactly my experience too.

That hell is seemingly the point.