Do you have any headcanons about how Vetinari ended up taking power?
I wrote a fic about his first day in power that vaguely referenced this and while I don't have like, a fully fleshed out story, there are a few bits and pieces that I sort of bodged together from things in the books and what I personally find entertaining about him as a character:
There's a bit in Soul Music which says that there was a rat plague in Ankh-Morpork shortly before Vetinari came to power, and that his solution was "tax the rat farms". It's unclear in context whether this means he suggested it at the end of Snapcase's time in power or if it was one of the first things he did after he became Patrician. I've just gone ahead and assumed that the rat plague was the last straw for Snapcase and that actually having a good suggestion was one of the reasons Vetinari was in people's minds as a replacement
That then leads us to ask, well, what on earth was he doing there? He's been in power a fair while even by Guards Guards but chronologically must still only be in his early 40s by then, to have been in his late teens in the 30-years-ago bits of Night Watch (and he can't be older than that, because it's made fairly clear that he's in the Guild equivalent of secondary school at that time, and Vimes knows that the two of them are approximately the same age). Given his canonically hilariously long list of postgrad qualifications, he probably went straight from Assassins Guild grad school to the Oblong Office, more or less. Conclusion: he was the fucking INTERN. (or possibly working as a clerk, but calling him the intern is at least 500% funnier)
Given the running joke about him being this weird posh dude who doesn't seem like a threat until you remember where he was educated, I would imagine that his whole "ah capital jolly good here I go getting slang wrong again" bullshit started here. We know that among the Ankh-Morpork elite, pretending to be stupider than you really are is something that can both keep you safe and help you get away with a lot, because we see Vetinari and Vimes and Sybil do it. So this is where he got his practice. Bertie Wooster the FUCK out of your working day, quietly get on with the things that need to be done while nobody's looking, and nobody will realise because they just think you're Madam's weird nephew with the shit beard and the puppy
So, bearing all that in mind, picture this:
Snapcase is dead. The important people (at least, the people who think themselves important) converge on the palace. In a small room off the Oblong Office is a young man steadily working through a large pile of paperwork. Oh, yes, that's Madam's nephew, you know... Havelock, isn't it? They ask if he knows what's happened, and he says no, he has no idea, he's just been working his way through all these regulations, and gosh, they really are very dull. And... well... nobody else is here. And nobody else seems to understand the filing system, or the rest of the staff, or anything really. But he does.
This guy's had a few good ideas when he's been doing the minutes at various meetings, that makes him a plausible candidate surely? And he's so young, so he's going to need a lot of guidance from helpful, experienced folks, right? How useful. He's just smart enough not to be an obvious puppet. Very handy indeed.
And the cream of Ankh-Morpork society being what they are (truly the cream- rich and thick) they don't realise until it's far too late that this lanky goth weirdo they'd thought would do their bidding knows everything about everyone and he's been quietly furious about the result of the Glorious 25th for over a decade. And, whoops, they'd somehow forgotten that he didn't spend all of that time on Guild postgraduate courses doing resits. Oh dear. And now he's their boss.