eg it isn't the fact that an immigrant can succeed, or that americans have free speech, or that america is a democracy, or that the us is multi-coloured, or that baseball is much different than rounders, or that mexicans and greeks don't also have corn, or that the expression of rights in the declaration of independence was a big step forward from locke or montesquieu. so these aren't the places i would look for difference.
i might add to my previous post that i think america is extremely accommodating of equality in its conversation, whereas other cultures are less excited about the bulge in the middle of the bell curve. i think many americans are proud of the culture's inclusiveness and the confidence of its citizens.
and i think as a young country, the us embraces the future more than most.