This is a favourite of mine that I never quite understand, that is foreigners just assuming the shit out of everything.

At my old work we had a few employees who were students from Hong Kong. Chinese customers would come in and speak a completely different language to them, and not even attempt to comprehend that they didn't speak the same language. I remember hearing one conversation where my colleague was trying to tell them she didn't speak Mandarin, and they just kept on ordering.

I have had people speak French and Italian at me. Not to me, or with me. At me. Most don't even bother to gesture what they want. They just damn well order it.

Another annoyance foreigners do, which I've only had from Americans, "Can I pay for that in American dollars?"

a. No.

b. No. Because this isn't the USA.
c. What are you? Stupid?

d. No. Due to b, and also... Your currency is worth jack shit currently.