You ever see the another American see the difference in how other countries treat identity and cause a culture shock that can seen on a richter scale?

I can imagine an American showing his "23 and me" results saying he is proud to be 90% German and Germans looking in horror thinking he is some kind of race purist because other cultures care about cultural knowledge and language skills to call yourself something instead of genetics.

You see this talked about a lot on indigenous and Mexico subs with American expats, but I wonder if European countries have the same problem.