Very true. There's a persistent notion in some quarters that the United States is a uniculture. Which it is clearly not to anyone who lives or has spent any amount of time here.
Shoot, I live in California, and not even this one state is a monoculture--very far from it. "You Californians" is scarcely less of a broad brush than "You Americans."
Still, there are things that can usefully be generalized about, and sometimes language differences are among them. It's not hard to find things that the majority of Americans say and that the majority of British people don't.
