Although this thread started with the question of self obsession, It seems to be migrating toward the idea of generalizations, which I think is more to the point.
Here is my perspective as a Puerto Rican American who has just moved back to Puerto Rico:
Here in Puerto Rico I have noticed that generalizations abound! Every time I express confusion over cultural or linguist differences, the invariable response is:
Well, Americans see it differently, they blah blah blah
Ive heard this so much I wanna pull out my hair! And I was born here in Puerto Rico!
America is geographically and demographically too large to make any generalizations that apply. There can be as much difference between a Californian and a New Yorker as there is between a Thai and a Lapp. So to make any sort of generalization that we are self obsessed, or anything else for that matter, is just nonsense. Yes, we have a HUGE media machine here that gets broadcast over the globe so it may appear that the American voice is loud, but we are just people like everyone else.