On Diction and Responsibility

Let's get this established: I love my family. I really do.  They're wonderful, smart people with excellent senses of humour finely honed by twenty some-odd years of interacting with me without completely losing their marbles (aside from my grandmother who quite literally lost her marbles, as in mislaid her collection of pretty little glass balls.)  In what I tell myself is some grand scheme of petty underhanded vengeance but in reality just stems from the fact that they're human and so am I, they occasionally annoy the crap out of me.  

Frequently, these things are linguistic; my default states of being are, a) Thinking About Words, and, b) Indignant, so it only makes sense that they should intersect.  I'm not talking about the communication gaps inherent in not only familial but also all human relationships - that's a subject for a time when my brain and I are actually on speaking terms, which we aren't at the moment.  I haven't let it have enough coffee.

What I'm thinking of right now, aside from my biological mum's overuse of "tidy" (find another word occasionally! you sound like a British housekeeper!), is my adoptive mum's habit of saying that something she'd told me or Dad to do "didn't happen."  This is, of course, grammatically correct.  It's not very stylistically shiny, being in passive voice, but would be technically acceptable even in writing, far less casual conversation.  

It's more a personal thing, I suppose.  If someone didn't do something they didn't do, fine.  Say they didn't do it.  If they get defensive, tell them to cut that crap out right now because being expected to take responsibility for one's actions or lack thereof is a terrible thing to have a snit about.  Saying it didn't happen, though, vacates that responsibility, in the process robbing that person of agency.  Pretty much anything they say is going to sound weak and self-pitying because you can't apologise or say you'll do it or fix it or whatever without self-referencing and maybe I'm just paranoid but the whole thing comes off really passive-aggressive, for all it's not intended as such.  

While I don't like having it pointed out that I've screwed up, I'd much rather be told that I screwed up and can thus own up to the mistake, apologize for it, and go about setting things to rights than have it made out that control of my action and inaction, as well as necessary tasks, lies in the hands of some arbitrary outside force.  Any thoughts on the matter?