I agree to the above. MMI is usually just used as a slight at people who think the DM is the arbiter of the rules.
I am having a hard time to stay diplomatic here..
lets say, some players want hard and fast rules to resolve any possible situation, some are more happy to have a dialogue with the DM.
Conversely, I have found "MMI" to be a criticism voiced when the dialogue has broken down (often more than once) so the player feels unmoored and upset with zero remaining effective recourse. Most likely, it's a spectrum.
"Mother May I" criticisms can be valid. Consider, for example, a player who wants to have confidence that they are making good, productive decisions that will help the group succeed, and will avoid feeling like "dead weight," assuage anxiety over "playing badly," etc. (These are all concerns I have personally had, so this is not a hypothetical, I have really been there.) A DM who responds to that with a flippant attitude, who pulls a Vader-like "I have altered the deal, pray I do not alter it further" move, etc. is one that will quickly convince me that my anxieties are both well-justified and impossible to address. Since emotion usually desires an outlet, complaining about it on a forum is a way to release that pressure and cool off a bit, in hopes that a more productive dialogue can follow...but frankly if the DM has already taken the aforementioned Vader approach I'm not sure there is anything that can be done.
And this is the problem people often deny or overlook about "rulings over rules." Human minds are not axiomatic systems. We struggle mightily with consistency and accuracy. All too often, we let emotional responses control our actions and decisions. When this is then compounded by the "rules" being inaccessible, present exclusively in the mind of their arbiter and not visible or tangible to those subject to those "rules," you have a massive amplification of the risks associated with such freewheeling efforts.
Of course, the immediate follow-up whenever someone mentions this is to cast summon straw golem and say, "oh so you want a game where there's a perfect, prewritten rule for EVERYTHING? That's obviously idiotic." And of course, it IS obviously idiotic, because no one is asking for that. There are, in fact, other options besides "they aren't so much
rules as
suggestions" and "Math 404:
Introduction to Transfinite Gaming." Because the thing so often left out is rules as
frameworks: generalizable rules, which do not cover explicit individual cases separately, but which cover a broad swathe of concepts and which can be expanded to cover new, related situations without needing any modification or rewrite (and which can be expanded to even more situations with minor tweaking.) Such extensible framework rules use a small number of rules elements to cover potentially infinite variety. One such thing is Skill Challenges from 4e D&D. Another is the "Ritual" move from Dungeon World. 13th Age offers its take on Backgrounds, its One Unique Things, Montages, and Fighting In Spirit.
"Mother May I" is certainly uncharitable. Sometimes it is so because someone is butthurt and just wants to rag on a perfectly reasonable DM who refuses to be browbeaten. Sometimes it is a perfectly valid complaint that "rulings not rules" has many points of breakdown that its fans either deny or overlook. There are solutions to these problems if people are willing to give up the illogical and false dichotomy of "either there are individual rules for everything,or there are no
rules for anything, just suggestions."