I must be a Norwegian American.
I grew up in Texas. Very outgoing, gregarious, sharing, talkative family. They smile a lot. I never do. Nor do I want or expect others to smile at me.
When strangers smile at me, it's like overload. I have no idea what they're thinking or doing. It's like being shined in the eyes with a flashlight. You can't see anything.
When I meet a person as equally reserved as myself, I smile on the inside because I can finally see a full person with all their subtle details and somehow they seem more human to me. Smiley people look like clowns to me, so I guess what I'm saying is that I understand Europeans when it comes to this.