Okay, but I'm looking for the sorts of questions one might need to ask oneself in the course of that introspection.

I think two questions are important: 1. What is the actual cause of my emotions? (I.e. expected loss of status, or just feeling cranky all day, etc.) 2. What part of my emotions is actually warranted? (I.e. am I over- or underconfident, overly stressed / too calm, etc.)

I disagree. I think the request is unreasonable. Yes, you can ask it politely, and thus cause no ill feeling, but it's still a request that would not plausibly be granted unless the asker has great power or status over the askee, which was not intended to be the case in the example. This makes the request presumptuous: I wouldn't make an implausible request, so to ask is to behave as if I had so much power over you as to expect you to drop your actual work to satisfy my laziness (and hunger).

That's what I meant with treating others as equals and taking responsibility for your own wellbeing. It's not easy to conceive of an example where you could do that and still ask for a sandwich but I think it's possible.

Always be sure about your midterm and longterm plans

Easier said, but nevertheless valid, as is the rest of your point about this one.

There too, training is key. Set aside a time every evening or every week where you review your goals. Like brushing your teeth, it should eventually become second nature.