Eh, I only said that because I didn't grow up in the US, and had to learn American ways to live and work here. America's a huge part of the world economy and international business, so you're probably going to run into one at some point (sorry, Earth).
But the US isn't the only place with different practices.
China has no time zones. New Zealand's Chatham Island has a 45 min time zone, as in UTC+12:45. Some institutions use lunar or cultural calendars instead of Gregorian time. Some don't use Arabic numerals outside of Western collaboration.
Time aside, the US, Canada, Chile, Colombia, the Philippines, and a few other places use letter-sized instead of A4 paper. Phone number formats are different everywhere. The time and decimal separators are different in many places. Time and timeliness (as in how important it is to start and end on time) differs by culture. Preference for information density vs simplifying cognitive load (in the UX sense) differs between languages and cultures. Red is a warning in some cultures and good luck in others. Not all colors are even distinguishable between cultures. Do you act casual, or formal? Keep your distance or offer a touch? Right hand, left hand? Is pointing OK? How long should you maintain eye contact? First names, last names? Many cultural systems don't identify people like that. Nodding isn't a universal gesture. Do you do a haka before events? What about a ritual blessing before a competition? There are SO many differences to consider in an international context.
Big companies have entire departments working on this stuff, not because they are ludicrously US-centric, but because it's so different everywhere.
I only mentioned the US vs Europe differences because that's what the OP asked for. Shrug. I'm not shilling for the American ways, just describing them. I wish we went metric decades ago, because it's a far superior system.
But the thing about standards: everyone has their own.