As an expatriate who has traveled through dozens of countries and lived long-term in a handful, let me assure you: different national personal characteristics are very real. Put an Englishman, a Norwegian, and an Italian in a room together and it is more than their accents that tells you who's whom. Or a Chinese, a Japanese, and a Korean for that matter.
Pick up your suitcase and get outside North America for a bit. The world's a lot more diverse and interesting than the education system might have you believe.
I've spent time in countries all over the world and my experience was not like yours at all. There were so many more important factors in guessing a foreigners personality than what their nationality/ethnicity was. What is their education level? What is their occupation? What is their economic background? If you want to stereotype then those were much better questions to ask than "chinese, japanese or korean."
Now if you want to argue that certain countries produce way more of one socio-economic class than another and that you're more likely to be exposed to people raised in that culture then maybe I can agree. But to just say, for example, all Nigerians are loud mouthed tricksters? No I don't agree with that kind of stereotyping.
>> Put an Englishman, a Norwegian, and an Italian in a room together and it is more than their accents that tells you who's whom.
Unfortunately, that's very difficult to know for sure, for instance because you can't just take the accents out of the people and see if you can guess their nationalities from their behaviours.
Also, I don't know how you can tell that the differences between an Englishman, a Norwegian and an Italian are due to their nationality and not just the difference in personalities you'd expect to see between any three people- say any three Englishmen or Italians etc.
Pick up your suitcase and get outside North America for a bit. The world's a lot more diverse and interesting than the education system might have you believe.