MEGA RANT TO BE TAKEN WITH A PINCH OF SALT!
Having now worked for two American companies over the past 4 years and having been to Boston, Texas and California, I'll give you my view, and what I believe.
We (British) see America as America-shire. Like Lincolnshire or Yorkshire but further away. The majority of British don't see American as foreigners, because you speak English, only with a weird accent, like people from Liverpool or Birmingham or London. So, we sort of expect you to be like us (Yorkshire people, Liverpudlians, Scots, etc) but you aren't.
Americans, whether visiting here or in your own country seem amazingly polite. Not just in conversation but on the roads. I watch you on your motorways and the number of speeders or people tail-gating is microscopic compared to Europe and Japan. I mean I see the giant Freeways opening up before me and I would hit light-speed but no, you leave massive gaps in the traffic, no meaningful speeding, no traffic weaving, even though it's legal. In Boston a woman in a car stopped to let me randomly cross the road. That was weird.
(Turn right on Red freaks my mind out)
Americans often appear to be over cautious, which makes Europeans / South East Asian seem almost feral in comparison, and many Americans never seem to relaxed around foreigners. (With some notable exceptions I work for. Namely one of the Trainers who is the funniest guy on Earth, but a chronic womanizer) It's like we want to trust you guys, but you've been beaten up by your own media so much that you can't trust us. We think, that you think, that we hate you. We don't, many of us love you.
Americans can appear to be insular. The whole most Americans don't have a passport thing, and never leave the US, does have an affect. That affect is you have beaten yourselves up, and become full of self doubt around foreigners, or that's what it appears to be. Very few Americans seem to relax around foreigners, unlike pretty much every other race I have met.
In mixed groups, the French, Germans, Swedish, Dutch, Chinese, South Koreans, Japanese, Israeli's and the Turks are more than happy to bicker, get drunk, talk rubbish, letch over women, argue and induce massive hangovers. Except Americans. Despite having been to America many times, you guys don't do that sort of thing. Which is very weird. It's like you isolate yourselves, which makes the rest of us feel you are either aloof or nervous or don't trust us. This comes out in other ways too, so it's a cultural thing. Americans are foreigners too
We expect you guys to be brash and loud: USA! USA! USA! We're #1, and from my point of view, you more often than not are quite the opposite. Which is disappointing.
Irritatingly you all seem to believe the entire none-American world hates you, and you constantly and quite irritatingly apologizing for it. Something you could have learned from the British Empire - never apologize for anything.
A majority of Americans constantly and irritatingly beat yourselves up over a lack of culture and history despite defining the entire worlds for the past 50 years. Which is sodding irritating too, a bit more pride in your own countries achievements wouldn't go a miss.
You do however seem very proud of your cars, which is misguided.

(Viper and Corvette excluded)
I learned to never get in a lift or a train with Texans. They absolutely psychologically cannot help themselves from talking to you. And we (British) don't talk to each other in lifts and trains. (that's the proper word for elevators by the way

)
Americans are the best presenters in business meetings.
You make the best breakfasts in the world. After the British. And is way, way, way, better than Japan that makes a breakfast with soup and rice and seaweed (madness!) or Europe with whole over-sold Continental Breakfast thing.
You guys do make the best coffee. And the best Eggs Benedict. And the best English Muffins.
Americans are chatty and easy to communicate with, and you guys often express emotions and feelings much better than British. We get some American versions of British shows, like Wife-Swap. The Americans are politely and comprehensibly talking their issues through and the British are clamming up, then trying to kill each other.
All American girls, with a proper American accents are cute. This is fact. There was a woman in our tech support department who was dressed like an American. Denim Jeans, jacket, white sneakers (trainers) and a NASA baseball cap. I was dribbling, just the way she spoke and acted, she wasn't hugely pretty but I just wanted to sit and listen to her.
Don't take anything I have said the wrong way. I love America, I love Americans. I love your shopping Malls. I'm in Las Vegas in August and I am so looking forward too it. I never think badly of Americans (as a nation) I've just learned to appreciate that you aren't British, and because of the proximity of your culture (MTV, Hollywood, Coke-Cola, The A-Team, NASA, IBM) that's pretty hard to do.
I hope I haven't offended anyone.