‘Herbs’ as ‘erbs’. I first encountered that in some Woody Allen film that revolved around Mia Farrow and unexpectedly efficacious Chinese medicine, and it wound me up every time I heard it (or should I say ‘eard it’?) which was of course All The Time. It has a H in it! Look! It’s right there!
I feel the same way about ‘an historic’ or ‘an hotel’, though I’m not sure if I’ve ever actually heard anyone say the latter in the wild.
I think I’ve pronounced chorizo about two dozen different ways over the years. I’m still not sure, to be perfectly honest.
They do to me, but I pronounce “squirrel” more like “squirl.” I’ve heard others pronounce it more like “squeer-ull” but not very often.
The only way I’ve heard it pronounced in the States is chuh-REE-zoh (or maybe choh-REE-zoh, with a bit less slurring of the first syllable), but I have no idea if that’s even close to an authentic pronunciation.
I have … in Paris. 
Those are the only ones I’ve ever heard, and I’ve lived my whole life in California. If there’s another way to pronounce it, I’ve never heard it.
I was surprised to learn that cilantro is pronounced with an “s” and not a “ch.” I always thought it should sound Italian, not Spanish.
It feels very weird to me that:
many places in the US have French names
many also have Spanish names
…and while many of the Spanish names are pronounced in pedantically-correct Spanish, almost all of the French names are FUBAR. If you want to have Nawlinz in Looziana, and Kordaleen in Idaho, then you better not mind when I take a trip to Lazz Veeguzz, maybe stopping in Santa Kruzz along the way, or if I refer to that border town as Eel Payso.
My favorite is Lyons, WI. On a road trip once, a friend said we’d be stopping in “Lions” for lunch. After looking at a map, I asked “Oh, you mean ‘Lee-ON’?” My friend glared at me and said “No, LIONS! This is rural Wisconsin, not France!”
Not far from where I live in Canada, there’s a shopping mall called Agincourt. My daughter, who’s lived here since she was ten, invariably corrects me when I use the French pronunciation. I just can’t bring myself to say “Ajjin-cort.”
Foyer, anybody? Anyone?
Okay, so I spent most of my life pronouncing it, um, like it was spelled. Foy-er. That is if I pronounced it. I mean I knew the word and I thought that’s the way it would sound if pronounced, and if I pronounced it–and I don’t remember if I did–that’s how I would have.
Then I read a mystery novel where the detective, kind of a snob, throws some shade on some people who pronounced it “foy-a [long a].” Like they were being pretentious about pronouncing it that way, and he would know.
So let’s see. Foy-er: Silly, because what you think it’s spelled like it looks? Southern culture: it is spelled like it looks. No silent letters in the south! Mid-level snob: pronounces it foy-a, laughs at the ignoramuses pronouncing it the way it looks. High level snob: raises eyebrow at mid-level ignorami snobs pronouncing it foy-a.
Now I’ve been through a similar thing with “aunt.” I’ve only known two groups of people who rhymed it with “taunt,” snotty bluebood Bostonians, and black people. My people are more likely to give the word two syllables (ay-unt). The insect is much the same but with a little less of a long A and more of a short A. But I got to eavesdrop on a person I know who said she always, always pronounced it the proper Boston-snob way, and she was lying through her teeth. She is a California native and she pronounced it “ant” until she talked to the snob.
I’m okay with never saying the word foyer again, but I’m gonna have a hard time with aunt.
When I visited family in Kentucky, I was afraid to try to pronounce any of the places. I live in a state with a Louisville and it’s “Lewis-ville.” I’ve been to a country with a Versailles and it was, yeah, never mind, I probably got it wrong there too. But hey, are we gonna say it like it’s spelled, or not? We could make up our minds here.
Just recently I ran into the word bas-relief. I know this word, I know what it is. I am not even gonna try to say it.
And Detroit.
I say it with the “sket.” In my experience, folks don’t consider it pretentious. They just think I don’t know how to say it, because they correct me gently. “And the bruSHETa to start! Will that be all?”
In Castilian Spanish, they would say “cho ri tho,” th as in “thing.”
My nomination for the OP is when I say “octopuses.” Most people want to correct me to “octopi.”
Ahem.
You have skipped a level of snobbery.
Fwah-yay
I’m currently struggling with what level of snobbery to apply to trompe-l’œil.
“Herbs/erbs” is the main thing that came to mind when I read the OP.
But I’m also trying to remember a scene in a movie–don’t recall the movie’s name–featuring prep-school guys teasing one of their number who’d come from a less-advantaged background, over his pronunciation of a ski resort. I think it was one in Switzerland, though I could be mis-remembering. Ring a bell with anyone?
To me, it’s people who pronounce “vase” as “vahz,” and “aunt” as “awnt.” Both are perfectly legitimate and common pronunciations, but to my ear I can’t help but hear them as pretentious affectations.
That’s easy: DE-troit! 
Octopuses all the way. Well, I’ll take octopodes, if you like, but only with a knowing look. Perhaps a raised eyebrow.
The difference between “vase” and “vahz”?
$200.
And not just “octopi”:
https://www.weeklystorybook.com/.a/6a0105369e6edf970b01bb083fe905970d-600wi
Oh, that’s a classic. Brits love to get sniffy about the American silent h in “herbs”, while blithely ignoring their own failure to sound the r.
H is a hotbed of snobbery: pronounced “aitch” like the French “hache” with its typically French dropped initial h (dare to say “haitch” and be damned forever), while “herbs” must be “Herbs” because of its initial h, despite its being cognate with the French “herbes”…with (again) a silent initial h. But that doesn’t count this time.
“An hotel” (because it historically had a silent h due to its Frenchness so the “an” made sense)…but with the h pronounced because “h dropping” is now a mark of plebby ignorance…but the “an” remains because, well, because, because they said at school that people who really know their English do it that way.
It all gets very tiresome.