Another easy example is location. Just browse through the introduction threads on this board. Most people that are not from the US will post their country of origin, while those coming from the US mention their state, not even bothering to mention their country. Try imagining people from other countries mentioning their state or province without their country. Most of the time you wouldn't have a clue as to what it's about.
Now I don't consider this as actually intended to come over like that, but it does make Americans appear as pretty full of themselves.
Just my 2 cents.
You must be mindful that this effect stems from one of several reasons.
1) While America is far from economically or politically isolated, good sized chunks of it are culturally insular. What 95% of the world calls Football, they call soccer, and they just don't care if they're wrong.
2) Some Americans legitimately don't give a shit about what goes on outside US borders.
3) Some do get used to the vernacular here. Because of the morons in our department of education, metric was deemed too much of a hassle to convert US students over to. This first came up in the 1970's or 1980's; the irony is had they pushed the initiative then, we would now have an entire workforce generation that is just as fluent in metric as US standard measure, instead of being the only major nation that doesn't use it.
It's funny, but where the education system failed us, many of us gamers picked it up. In tabletop gaming and online wargaming, I routinely measure my range in meters and the weight of my weaponry in metric tons. 1.6 is permanently ingrained into my head as the conversion from kilometers to standard miles.
Likewise, we bother with internal vernacular, assuming that everyone knows the difference between Tennessee and Nevada. Now if someone starts spouting Canadian provinces I know those, and I'm aware a prefecture is very likely to be somewhere in Japan, but not all Americans have this working database in their heads.
4) Same with time zones; most have the capacity to correlate the four continental US time zones, but outside of this comfort zone they'll have issues. Unless we travel a lot, most of us can't/won't anchor ourselves on GMT for universal reference.
So, by definition America isn't always necessarily full of itself (well, except for Texas
), but America usually does what America does, and whoever else is paying attention just isn't an issue for many.