When "flipping the role", it is important to keep all the parameters identical! In other words: you have to be able to empathize enough with the other person to be able to incorporate their needs/wants/capabilities in your "mental model" of them.
A practical example: when I'm having beers with someone who is studying (and very low on cash because of that), I very frequently pick up the entire tab. Why? Because I can still imagine what it was like as a student myself and sort of even imagine that that person will hopefully do the same when they eventually start making money. Vice versa, I would never expect them to pay more than "their own consumption" and would flat-out refuse to let them pick up an entire tab. (Unless there is an obvious indication they are swimming in money.)
This is basically what empathy means: being able to incorporate a workable mental model of a different person and being able to think from that perspective. Of course, there are cases where you have no clue as to the other persons background/situation, etc. In this case I'd suggest expecting as little as possible, because it would be easy to go wrong there. But you can avoid this situation by being observant and by asking about them. A simple "how are you" is a good start.
I totally agree with you--I just find that a different enough thing from simple role reversal that I wouldn't call it that.
Your example about money is one that comes up a lot for me. I've been a student for only a few weeks, but I've been unemployed and broke for more than a year, and do my best to avoid awkwardness about it--I'll accept someone covering me but try to make sure they don't feel obliged to. I do worry about it happening too often, though, because while I certainly would repay the favor given the means, I'm not going to have the means in the forseeable future.
I'm working on a list of question types which come up frequently in day-to-day life but which I haven't yet found a reliable, rational way to answer. Here are some examples, including summaries of any progress made in the comments.
Practice the ability to judge how important something is to change, making sure to examine your criteria of importance. Identify the reasons you want to change it, and try to normalize your emotional response to the facts. Learn about the difficulty of changing a thing by investigating other peoples' attempts to. Be aware that, the less one knows about a field, the less one is able to judge how difficult a task in that field is. Ask an expert if you need to. Another heuristic for difficulty of changing something is that the closer it is to one's own mind, the more control one has over it. When you know as much as you can, do a cost-benefit analysis.
Unreasonable requests are those which would only be fulfilled if the asker had power over the askee which they do not, which represent an unequal exchange between equals, or which are not actually possible. We don't want to make unreasonable requests because they are at best unfair social impositions and at worst rude and damaging to relationships. This is complicated because requests between friends aren't about direct exchange; it's expected that sometimes one person will need help, and sometimes the other will, and in the long run it'll even out. In a strong friendship where both people have treated each other well, it's more appropriate to ask for a large favor than it would be to ask a relative stranger the same thing.
The difficult requests to judge are those where the power balance or strength of the relationship, or the values of what's being exchanged, are unclear. That is, they require a more accurate judgment of either the relationship itself or of the other person's needs and abilities than one is confident of making. As in the previous question, specialized knowledge can help predict how much trouble a given request might be. In the specific example above, one would need to understand the cost of lending an ear, in terms that could be compared to the benefit of venting. Prior communication is the best way to achieve this; basing an estimate on similar past situations is also good. Knowing nothing else, use an assumption of equality and the basic responsibility for oneself as heuristics. Finally, how close you can get to the edge of what's acceptable may depend on how much you trust the other person to tell you if your request is not reasonable (rather than acquiescing resentfully).
It's possible to minimize the necessity of choosing between these two things by doing work which is enjoyable and taking breaks after earning them. When the two types of activity do conflict, one way to get around it is to use time that wasn't available for work anyway to do unproductive things. Another is to have (and frequently review) clearly defined medium- and long-term goals, and weigh short-term choices against them. Doing this regularly may make it easier to judge activity choices on the fly.
No comments yet, but here are some questions this raises for me: What does it mean to have reached your peak in a skill--is there actually a maximum amount you can usefully learn and practice, or just a (potentially variable) point of diminishing returns? Is it possible to know there's more to learn but not be able to learn it?
So far, the only mitigating factor I've found is my overall physical and mental state. Being hungry, tired, or stressed makes it easier to fall into the anger cycle and harder to get out. Therefore, taking care of myself in general helps to prevent it, but it's not always possible to remedy those problems after the cycle has already started. When circumstances permit, physical activity may provide an outlet for the energy that keeps this cycle going.
A conversation offsite led to the following: Manipulation involves both deliberate instigation of emotion and trying to persuade someone to do what you want, but isn't defined by either. (The first one describes gestures of affection, and the second includes ordinary debate.) The definition we settled on was "using emotion to bypass someone's normal decision-making process." Trying to get someone to do what you want is not inherently manipulative; trying to make them feel something so that they will do what you want is.
Naturally I'm looking for ideas about how to answer these questions, including links to earlier thoughts about them[2], but you get bonus points for supplying actually usable heuristics, rather than just opining on my examples. But I'd also like to hear it if you've got any questions of your own that fit this form. Consider it a sort of lowbrow subset of open problems--difficulties you're aware of having on a regular basis but haven't yet been able to solve.
(Tag suggestions are appreciated. I'm unaccustomed to using content tags, so I made some guesses based on the site's tagcloud and what's on the similar Open Problems post.)
[1] I actually quite like the Serenity Prayer, despite being entirely nontheistic, because it presents a set of traits to aspire to for specific purposes I can get behind.
[2] Until I've read the entire LW archive, I'm constantly paranoid that anything I post will be a second-rate rehash.