While visiting DC, Aussie John Quiggin notes that Americans are friendly -- friendlier, in fact, than his fellow Australians (except for the Brisbanians/Brisbanites/Brisbaniacs). This seems at odds with my own experience, as I found Australians to be friendlier than Americans. The people of DC were of about average friendliness, so it's not an issue of which Americans he's met. These two observations, while seemingly contradictory, do appear consistent with a larger trend: people who go abroad typically report that the inhabitants of their destination country are very friendly.

Off the top of my head, I have a couple theories as to why visitors to foreign countries generally find their hosts to be notably friendly. It may be an issue of lowered expectations. We can come to (sometimes subconsciously) expect foreigners to be notably unfriendly -- put off by our alienness, perhaps, or we're both unable to overcome the culture barrier. Against this low standard, otherwise average friendliness shines. It may be an issue of how people react to foreigners versus natives. It's possible that people in general tend to be friendlier toward those who reveal themselves to be from far away -- out of a fascination with encountering someone out of the ordinary, or a desire to help someone who may need more help due to being away from familiar surroundings. It may be an issue of under-estimation of the friendliness of the people in our own country. I know I'm surprised from time to time at how much more friendly people in Pennsylvania are than I expect them to be (despite having lived in the state for 17 years, and off and on for 5 more).