Have to say though, americans are not exempt from this either. We were walking along the 'looooooong' queue to get into Finding Nemo: The Musical, where this mother-daughter combo walked up our heels the whole time then even as we were going in the door, walked in front of us, and ran down the front, then realised they couldn't get down there and tried to push in front of us again.
Unfortunately, rudeness us a multi-national thing. Interestingly, I notice quite often, and this must be a cultural thing but here in the UK, I always hold the door open for people and when they walk through, they say thanks. It's not a biggie, but it's nice when someone says thanks.
This year when we were out I notcied a lot of people just walk straight through the door like I'm some sort of door man. This one time at Premium Outlets, I actually got a reaction. I held the door open for a guy coming out of the character warehouse who just walked through with his kid, not even acknowledging, so I did the international 'what gives' gesture and he actually responded and went....'oh thanks'. Maybe not a biggy but it's a pet peeve!