Adopted Koreans

In my generation, born in the 70's, growing up in Sweden, there was a lot of Koreans adopted by Swedes. Most schools had a few kids born in Korea, but as they were raised in Sweden by Swedish adoptive parents from a very young age they're basically as Swedish as they can get apart from their Asian looks.

Unknown to many, he was actually raised in Sweden and goes by the name Lasse Svensson

When I'm in Sweden I don't really think about it and apart from briefly noting that they're of Korean ethnicity in my head when I meet one there's nothing really separating them from other Swedes. When I'm in Sweden this comes completely natural.

However, a while back I met an old Swedish friend here in Tokyo for drinks and he brought with him another Swedish friend of his own who happened to be an adopted Korean. This caused my brain to completely short-circuit... 

I have two basic settings in my head; one is for interacting with Westerners (in Swedish or English doesn't really matter, the setting is the same) and the occasional Japanese who grew up overseas or for some other reason is fluent in English and get the jokes. The second setting is my Japanese mode which I switch to when interacting with Japanese people. Obviously the default language here is Japanese (or in more rare cases simplified English) and all the Japanese unwritten "rules" on how to interact with the person in front of me come into play (what is my relation to the person in question? Who is senior? etc. etc.). I've lived and worked in Japan long enough now that this comes natural.

What caused my brain to completely short-circuit when meeting the Swedish-Korean guy was to have in front of me a person looking completely like a Japanese guy making my brain involuntarily switch into Japanese mode (he was dressed in a suit as well as it was after-work, further pushing my brain into the Japanese-business mode). But every time he spoke, with a heavy West-Swedish accent, it made my brain switch back to Western mode. My brain kept switching back and forth, short-circuiting several times until I hit the 4th beer as alcohol often makes my brain settle on one mode and puts the other one to rest...