lolwut? Nationalism is arguably the only thing that makes countries successful. If you don't love your country then what are you living there for? It has turned countries that were shambling ruins into world powers.
I don't care how much power my country has. I care that the people in and outside my county are happy (and if a country has pride in that, that's fine.) That doesn't require being a world power and aggresion. Take Norway, for example.
And no, I don't really love my country and ever since the end of the Cold War (and even during it we did done malicious stuff) I believe it has had a primarily negative effect on other countries. The only reason I live here is because I was born here. Granted, I am glad I live in a Western democracy that respects our rights, but we could go a lot better.