Nationalism
I hate nationalism, personally. In the case of America, it's just feebly trying to come up with half-baked defenses when some foreign country brings up our numerous faults. Because of my extremely low opinion of America, George W. Bush, and the United States Government in general, that I refuse to stand and say the Pledge of Allegiance once a week. I feel no need to pledge undying allegiance to a country I hate. And yet, as much as I hate my own country, I know that I have to deal with it for now, since I have no means of fleeing the situation, and no power to try and change it.
One of my friends has an almost irrational hatred of everything British. Granted, she is an extreme Irish nationalist (even though she's only 1/4 Irish and born in America), but every time Britain is brought up in a conversation, she scowls and denounces them. She's actually a member here, but she began boycotting it once she learned it was British-run.
Now, I know that one should feel proud of their country (except Americans), but sometimes that love can blind us to everything good about another culture that you happen to hate because of an event centuries past.