I’ve seen posts online or memes about it, mainly discussing American people who think the internet as a whole is US-centric despite the topic at hand taking place in another country (nothing to do with America), for example: someone wrote the date format as 30/10/2020 (using the EU format) but some American was like “THE CORRECT WAY IS 10/30/2020” when they fail to realize that user is not American at all.
Is US defaultism real when they travel abroad? They assume the $ is legal tender worldwide in countries where their own currency is used more (the only thing that’ll work is exchanging it but not for direct transactions). I’ve heard an American woman went on a tirade whilst in France as the cashier refused a $20 bill when the prices are in EUROS (WTF?) or being like “SPEAK ENGLISH!” in non-English speaking countries.
The US invented the internet (and the UK invented the world wide web), so English is the lingua franca of the internet for better or worse. Most people on the internet who speak English as a first language are from the US, and with the algorithmic nature of most of our online interactions being borderless, people in the US get fed non-US content all the time. If there’s not anything obvious signifying that they are seeing content from another country, confirmation bias will lead them to think it is US-relevant content.
I will say, on the money thing, there are a lot of countries that use USD from an official (or unofficial) capacity. The US is also pretty cashless at this point, so it’s possible that people have used their card overseas no problem, and not realized that their bank was doing an exchange in the background. Then they get to somewhere cash-only that doesnt also take USD, and suddenly experience their money is not good. Still stupid to be a dick about it when it’s your own fault, but idiots all around the world respond poorly when subject the the consequences of their own mistakes.