Been over that side of the pond a few times and strangly enough wether the cashiers sit or stand wasn't high on my list of notable diffrences.
The most obvious diffrences that struck me....
1)Except a few parts of New York, everywhere else over there was designed so you had to be TOTALY dependant on the car. Public transport seemed to only be used by an underclass of poor folks and trying to actualy walk anywhere was just about impossible.
2)I was hyper aware of the cops all being armed! Every time I saw a cop, my eye would be drawn straight to his sidearm.... This won't be the case for all Europeans of course, some other european countrys also have armed police. I noticed one in Belgum just last week!
3)Larger, lower density housing.... a town of a couple of hundred thousand over there would typicaly take up five or six times the land area.
4)European men don't "fall on their FANNYS!"

We are two nations seperated by a common language

5)The majority (Of those I encountered) had even less interest in politics especialy world affairs than the average Eurpoean.... Though that may have changed a little since the events of 9/11 which fairly forcably raised the profile and importance of such things.
6)Your TV sucks! The shear volume of adverts makes watching ANYTHING pointless "But I Clousaue can identify the murderer... it was...""Mr Muscle oven cleaner for all your kitchen needs..." WTF! They don't even flag that your going to adverts a lot of the time!!!!