I think that's a commonality of most locales. Pop/soda/coke is particularly divisive in the US, for instance. You can encounter genuine friction using the 'wrong' word ordering at a bar or asking directions in a grocery. I get friction for having adopted "y'all" because I like the you/y'all/all y'all construction in northern states because it lets me communicate exactly which 'you' I'm talking about.

Lots of people have a "well at least we don't talk like those hicks/rednecks/bumpkins/yeehaws/yeeyees" as if the people from there aren't saying precisely the same about you.

There's a fun quiz (though I think it is US only, unforutunately) called How Y’all, Youse and You Guys Talk by the NYT that was eventually turned in to a book with the same idea that is sometimes surprisingly accurate in guessing your geographical situation based on the words and pronunciations you use. https://www.nytimes.com/interactive/2014/upshot/dialect-quiz...

There's another aspect to the discussion as well, which is code-switching. The idea being that you have one way of speaking to, for instance, your friends/family vs coworkers/boss. Some people have gone to great lengths to demonstrate their ire at not being understood in the dialect they were raised on, and many people are shamed by their communities for "being weak" or some such because they "speak white" at work but not on the corner, for instance.

Edit: fun example ->

What do you call something that is across both streets from you at an intersection (or diagonally across from you in general)?

kitty-corner

kitacorner

catercorner

catty-corner

kitty cross

kitty wampus

I would use only diagonal for this

I have no term for this

other

NY Times almost got it with Seattle! Although my weird hybrid accent was definitely something that isn't fully in line (and I also use y'all because its fun.) I loved my sociolinguistics courses in university, although definitely felt a bit self-conscious at times.

You may be onto something with the first point though: while (southeastern) Brits may chuckle at northerners calling lunch "dinner" or the southwest sounding like farmers and pirates ("ooh er! combine 'arvester!") Americans do enjoy mocking words like "fortnight" and the pronunciation of "chewsday, innit?" too. So maybe everyone just mocks everyone else and I'm reading too much into the trans-Atlantic angle. After all, the way you speak is like a constant shibboleth and that's why I default to "what's your background?" instead of "where are you from?" in very cosmopolitan places.

Edit: Kitty-corner was the giveaway for Seattle, Spokane, and SLC. Although the one I always think of was this Starbucks which used to have another Starbucks kitty-corner from it in downtown Vancouver: https://maps.app.goo.gl/LPSk9XRaJMnDUGa66