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