Ethnic peoples have tight communities and millennia-old traditions and celebrations to bring them together to laugh, cry and fight in grateful praise of God, family and culture.
We of Western European descent claim regions of the Americas to define our belonging, and those lines are ever more blurred today in our mobile society. Our ethnic identity arises from a geographical point of reference: Midwest, East Coast, West Coast, Southwest...etc.
Depending upon where you grew up, you say: purse or pocketbook; couch or divan; highway 101 or the 101; y'all, or youse guys; kitty corner or catty corner; next week or this coming week; and, knapsack or backpack.
If you end your phrases in prepositions, like "where do you live at?" or add "at all" to the end of a query, you're from the Midwest. They will invite you to stay longer or stay over, and you will be expected to know to decline because no one would want to be an imposition.
If you put "the" in front of a highway number or street name--even if it makes zero sense such as "the El Camino" (which translated means "the the road")--you're from the West Coast. Ditto if you could correctly order a skinny half caf two shot latte in a local coffeehouse before Starbucks went national.
If you talk faster you're from the North, and slower, from the South. Southerners will put a lacy blanket of gentility over any disparaging remark by adding "bless her heart." Northerners do not talk to strangers in the elevator or on a train because that's suspect behavior. Southerners will mean it but not say it. Northerners will kinda mean it and say it forcefully.
If you're from Texas, you ask, "How are yooooou?" And, you expect a one word reply. If you don't own a gun they'll know you're not a native. If you don't buy a gun soon, they'll know you "just ain't right."
Highway, Interstate, Freeway, and Parkway can all mean the same type of road. Soda, Coke, Pop, and Tonic can mean any type of fizzy non-alcoholic beverage.
So for many of us, our cultural identity is defined by mannerisms and lingo, not by background, religion, shared history spanning the ages, or food--unless you count the yummy regional specialities like North Carolina pulled pork, Memphis ribs, Iowa corn-fed beef tenderloin, or Texas smoked beef brisket. (You can tell I'm a carnivore.)
We celebrate the diversity of America, especially in the summer, with Fourth of July, Memorial Day and Labor Day picnics. We shoot off fireworks and eat potato salad. We take vacations to Disney World and the beach. We pass each other on I-95 or I-80. We share a culture of sorts.
But it's not the same.