Okay. But IMO, you also have consistently provided definitions that under examination don't seem to separate the 2 with respect to whether they are mother may I. So, for me it appears you are consistently saying two different things. That's frustrating for me as well - but I'm confident we can get this sorted out.
*Note: I'm not blaming you. Defining stuff just the right way is hard!
I fully agree that those are different. So let's start here. Are both of those mother may I? If not, can you define mother may I in a way that exempts the scenario that isn't? I think for me that's where I keep getting hung up.
The former is not, the latter is.
Various things (many of which I have said before, perhaps in different words) may serve, though I have said repeatedly that this is a line which can only be drawn by human judgement, not by strict and unbending adherence to a rigid line. This is because it will always,
always be possible to dance on that line and do
just enough to respect the letter of the definition while subverting the spirit thereof.*
- Does the DM have a literal prefigured list of approved actions, and anything not present on that list is impossible, no matter how the players might approach it? That is trivially MMI, and looks nothing like "sometimes, albeit rarely, the answer is no," while being identical to "the answer is almost always no, unless it tickles DM fancy." Note that this a form of MMI which doesn't even need to rely on DM adjudication (which is somewhat unusual, at least in my view of the term); a ruleset could do the same thing, e.g. the skills in it could have very specific, defined uses, and if anything "off-label" is verboten, then it is the ruleset (or the designers) doing the MMI. The effect is no less frustrating, but it is mildly more manageable as a player because the rules are visible and can thus be actually critiqued and (perhaps) addressed, which is where the DM adjudication enters the picture; a DM playing a closed-ended ruleset with a draconian, unbending commitment to perfect RAW is going to end up contributing to the MMI by shutting down any effort to address the system's shortcomings. Also noteworthy, this has nothing to do with railroading; a pure sandbox, no-plot, "no fate but what we make" game can still be affected by this.
- The DM has an invisible, perhaps even not actually known to the DM herself, list of what is pre-approved and everything else is presumptively rejected, where the players cannot find out what is on that list without trying things and being told "nope, you can't do that." This is the "classical" form (though AIUI the person who coined the phrase intended it more in the preceding sense), where the players have no real way to know what they're "supposed" to do except by learning to read the DM's mind. "Pixelb!+@#ing" is a classic example, drawing a comparison to one of the ways classic point-and-click adventure video games could become tedious and frustrating, where you must click on exactly one correct pixel in order to achieve what you want, otherwise you fail (and may even die!) This, again, emphasizes the "nothing is permitted unless explicitly approved, you can't find out what is approved without consulting the arbiter, the arbiter is capricious or inconsistent, and you will not ever be capable of making the arbiter budge" stuff.
- "Damned if you do, damned if you don't" syndrome: situations where it doesn't matter whether you use resources or not, come up with a plan or not, or negotiate with the DM over something or not, the end result happens anyway. This is a twofer of MMI and railroading, one might say railroading by way of MMI, as opposed to railroading by way of trickery (e.g. Illusionism, quantum ogres, fudging, secret retcons, etc.) This was on display in the Rustic Hospitality situation, where the players got....nothing whatsoever that they couldn't have gotten by just hoofing it into the forest for an hour before making camp. In this case, efforts are usually invalidated not by being told "no," but by being adjudicated into irrelevance most of the time. (Again, rare instances of disallowing something outright are okay, so long as the DM is being sincere, forthright, and respectful about doing so, and instances of disallowing in part rather than in whole, with opportunities for the players to improve or redirect things to get more of what they want by taking risks, are a great way to avoid these pitfalls.)
- "Miserly" or "curmudgeonly" DMing. The latter refers to DMing which treats every player effort at improving their situation as inherently forbidden unless an arbitrary, punitive threshold is met. Often this takes the form, as is common with MMI, of paying lip service to the player's ideas, and then (intentionally or not) giving those ideas a snowball's chance in hell of actually working. "Oh you want to persuade the skeptical Duchess to try to help your party that is trying to save the world? DC 30 Persuasion check, with Disadvantage." The former, "miserly" DMing, instead denies the results, as opposed to the attempt: "oh, sure you can try to persuade the Duchess. Give me a Persuasion check. 22? Not bad. She declares that because you have claimed a noble goal, she has graciously decided she will not have you executed on the spot, but you'll get not a ha'penny from her, nor a single partisan." Point being, this technically let the player do what they wanted to do...it just had no actual impact. Curmudgeonly and miserly DMing can sometimes be identified from single extreme cases like the above, but in general they will require observing over time to detect...which means you usually can't figure out they're there until you're already invested and entangled.
- Excessive overuse of the real world, or more commonly the incorrect and faulty understanding that the DM has about the real world, as a standard for what is possible in a fantastical world. This, I grant, is pretty subjective even compared to the other examples, but it's still relevant. There are a LOT of DMs out there who think that feats which Olympic athletes achieve on the regular are legitimately physically impossible. A number if DMs have faulty, Aristotelian understandings of how physics works, and tend to get quite belligerent if you prove to them that "it can't be done by an out-of-shape nerd, therefore it's superhuman" is a bogus standard. And, as with the first point, this is one that can appear anywhere; many folks have a really erroneous understanding of what a well-trained archer can do with firing large numbers of arrows reasonably accurately even while moving (e.g. Mongolian horse archers were terrifying because they could shoot very rapidly, with high accuracy, while moving at high speed.)
Are these finally enough? I have said most of them many times, often without comment (other than getting perhaps one or two likes from folks who agree with me, so I know I didn't just shout into the void.) My position has not changed. MMI is a problem of faulty DMing where extreme and unwarranted skepticism, denial, restrictiveness, or miserly adjudication stymie players left and right, very often resulting in players not being able to achieve
anything at all that they attempt to, unless that thing happens to coincidentally align with the DM's existing preferences (preferences which will get absolute authority and which cannot be challenged, questioned, or altered in any way.)
As an aside, though it is properly speaking irrelevant, I expect some people (though I doubt you will do this) to respond to this with some whataboutism. "What about unreasonable players?! Are you saying players can never do wrong?!" No, I am not. Players can obviously be petulant, demanding, irrational, narcissistic, domineering, etc., etc.,
ad nauseam. Unreasonable players are of course a problem. However, this is a total nonsequitur, it does not rebut any part of my argument whatsoever, it merely tries to replace the current discussion ("what is MMI? Does it even exist? If so, is it bad? If it is, how should we deal with it?") with a completely different discussion ("can players be just as bad as DMs in behavior terms? Is one problem worse than the other?") This is a distraction, rather than a valid rebuttal.
More importantly, it is not the players who are declaring special authority; it is not the players who claim to exercise absolute power; it is not the players who are claiming that their judgment is beyond question. It is the DM doing these things. Anyone who does these things, regardless of their motivation, deserves special, heightened scrutiny. That is not unfair. That is an inherent result of their claim to special, heightened status in the first place. Those who claim authority open themselves to greater scrutiny than those who do not. It is that simple.
*This is related to the problem of "legislating morality": moral judgements inform our laws, as they should, but our laws cannot act as a guarantee of moral behavior. The moment you try to replace actual human judgement with mere enforcement of law and no more, you invite abuse and amoral or even immoral behavior with an excuse already loaded and waiting to be used.