America was a start-up created by a dozen or so entrepreneurial people who were rebelling against an aristocratic, overbearing empire. They were scrappy, quick on their feet, smart, hard working as hell, and (mostly) open-minded to whoever could help their improbable cause. Kind of like Silicon Valley start-ups. Except for America's founders the stakes were higher and urgency greater.
When George Washington became the first president of the United States, he rejected regal titles like "His Majesty," taken from the British tradition. Instead he made sure "the titles and trappings were suitably republican and never emulated European royal courts." He said he was to be called "Mr. President."
I believe this relaxation of formalities is a component of Americanism. I'll call it an ethos of casualness. Europe's different. EU passports, for example, list your degrees (Dr., PhD, etc). Or when introducing someone's biography at a European business conference you start with his titles and degrees. I remember the senior journalist Martin Wolf being introduced at the St. Gallen Symposium as first a graduate of LSE, followed by his professional accomplishments. In a start-up environment, by contrast, you don't have time to flatter the status sensibilities of everyone in the room.
To be sure, although America has let go of the Victorian era more than Europe on the whole, there are exceptions. "I don't understand you Americans: you wear jeans to the opera but insist on wearing clothes at the beach." I.e., Europeans are more casual about nudity.
I like casualness. It maximizes commonality instead of difference. When everyone's name appears the same way on a passport, what they have in common — a name and citizenship — is the focus. If jeans and t-shirt are the attire guidelines, everyone can comply; if Italian suits are the standard, not as much. In this way casualness emphasizes similarity by focusing on a common denominator.
My upbringing stressed casualness and affected the way I think.
First, I grew up in the most casual part of America. There's only one restaurant on the entire west coast which requires men to wear coats. New York City, by contrast, has 13 such restaurants. Clothes are just one part of this, but they stand for a lot: in California you might well see Sergey Brin or Steve Jobs wearing jeans at a nice restaurant, as I have, but you would never see Henry Kravis doing the same in New York. California's billionaires blend in.
Second, at my high school we addressed all of the teachers, including the head of school, by their first name. Several teachers had advanced degrees — we still addressed them orally and in writing by their first name. Head of School, janitor, Chair of Science department, freshman student, security guard: Mike, Jason, Nancy, Jim, Kevin. There also was no dress code. I wore sweat pants to school many days and sometimes my teachers did the same.
Third, I had little interaction with the institutions that usually prize formality. People with religious upbringings get steeped in hierarchies, traditions, protocols, history. Not me. I also had little interaction with high culture (cuisine, fashion, or the arts).
The ethos of casualness came from my country, city, school, family and it's had an impact on how I think. It could explain why I'm skeptical of certain formalities. When someone dresses fancily, I sooner suspect he is trying to signal wealth than that he actually likes the clothes. I harbor related skepticism of people who talk about how much they love sushi or fine art.
As I've gotten older I have begun to selectively emphasize formality (and thus difference) in certain dimensions, such as use of language. But these are the selective overlays on a casual base.
Bottom Line: The ethos of casualness is a component of Americanism. Casualness maximizes similarities over differences. I am a product of this culture — I prefer casualness and I harbor skepticism of certain formalities.