In answer to GreyWolf's question:
At the risk of making overly broad generalizations, Americans both at home and abroad seem less aware of their own paradigms than many of the older cultures.
There are enough thoughtful and considerate Americans around to offset the sophmoric arrogance typical of some tourists, military and businessmen, and that sort of rudeness is probably not what prompts riots and burning effigies. However, we've spend several decades exporting our social constructs and leveraging our economic powers at the expense of local people and governments, and that aspect of America gives every charismatic demagogue enough evidence to get a significant fraction of their populace motivated. If other contries spent billions of dollars corrupting our politicians, or supporting cultish religions, or constructing corporate fiefdoms here in the United States, then many Americans would be quite justifiably angry. We often seem to have such a huge blind spot regarding the other country's perspective.
On a more personal level, I've usually had interesting conversations everywhere abroad, because most people seem very prepared to deal with us as individuals instead of the generic "ugly American."
On the other hand, I'm very Texan when overseas, and maybe that helps break the barriers somewhat. (But I've been asked about J.R. in the boonies of Timbuckthree ... geez!)