Well, the "greatest country on Earth" crap does piss me off.
Well, you can admit that the fundamental idea of the United States of America is great. The one proud thing about America is that it has managed to sustain freedom and remains one of the most democratic and free nations in the world. As many problems as there are in America, we are still undoubtedly quite great. I agree that our arrogance is unjustified, although I believe that the crazy nationalism has more to do with a small minority of people.
Now this stuff does annoy me. At this point in history there are many countries (like the whole of Europe other than some of the Ex-Soviet states and satellities) which have similiar or even more open instutions than exists presently in the United States. I don't believe at this point the United States has a greater degree of freedom (and what does that mean, anyway?) than the Republic of Ireland does. Yet Americans still act as if they have a monopoly on "freedom and Democracy".
Personally I don't like the Republic of Ireland much either, I consider myself "a human being by birth and an Irishman by accident" and things would be saner if Americans adapted the same approach.
This isn't to say that there are things about America that aren't great.