"Can I get?"

[Minniemountain]

No DH you can not get cup of coffee because you don't work in this cafe.
He won't change how he asks though

If I'm behind someone in a queue who says this , I have to clamp my mouth shut to resist the urge to hiss in their ear , 'have , the word you're looking for is have'

Do you correct people who tell you what they got for their birthday?

I am Scottish, in Scotland. It's not rude, as long as you say please and thank you. But if you're English (or possibly from Morningside), then presumably it is a dreaded Americanism and therefore terribly rude.

'Give me' is way worse.

I'm not English and I'm not from Morningside either. I'm nowhere near the Central Belt.

Worst example of this I've encountered:

Can I get a toilet?

Meaning May I go to the toilet?

Well, you can't blame this on Americans. Americans avoid the word "toilet" whenever possible.