Kestrel said
The don begs to differ.
Shh, The Library is an exception to nearly every rule.
Ruby said
I've had plenty of characters do very mundane things. Especially going to the bathroom, what with the epic example of 'And then he pissed in darkness.'
Don't know if humour.
In all seriousness: Not all mundane things go away, it's usually the little mundane things that tend to go away when you're constrained for space. Because pacing is a thing that must be followed lest you spend three pages describing the discolouration in your character's urine, which services no practical purpose beyond "and something is wrong with them".
It's what makes small, clever details all the more enjoyable when you realize someone had to sit down and figure out a solution to the limited pacing they have. Basically speaking though, mundane acts fall under two categories.
A. Characterization. IE: "Alice chews her lip" anytime she's in a situation where she needs to think under pressure.
B. The consequence of something. IE: "Bob is a coward who pissed himself in the face of uncertain danger."
Sometimes it's also used for useless-but-not-destructive things like Rule of Cool as well. IE: "Sam the detective pulls out a cigar."
Jig said
In fairness, it bugs me in general fiction anyway. I think I notice it more in RPs because (outside collaborative posts), dialogues are almost impossible, so I think people compensate by almost writing in mini-monologues, as opposed to how people I know talk to one another.
That's a pacing issue inherent to PbPRP and the fact that most people have a rather poor sense of spatial contextual awareness. Specifically in relation to the "time" and "physical" sensors. (ex: Character Bobby is in a fight. If he says more than one short sentence, he's already completely abandoned outside awareness of the situation. Character Sally completes an entire, complex piano tune that takes twenty minutes over the course of a two minutes conversation. Character John paces as he talks, but leaves long lurches in his dialogue without any physical contextualization through body language that would indicate why he paused.)
Then again, I don't expect most high school students to understand what spatial contextual awareness even is, so I can't fault them for not knowing how to apply it in writing.