In the United States, we pride ourselves on being patriotic. We love our country.
Patriotism, however, is different from a political ideology known as nationalism. Nationalists believe that a country should not be a "melting pot," rather it should have one look and feel and exclude others. This includes believing their country is better than others, and sometimes puts them in opposition with other nations.
Hitler, for example, was a German nationalist. Dictators often choose to emphasize nationalistic loyalty to control their populations. That's the case in North Korea, where current dictator Kim Jong Un infuses nationalism into every aspect of people's lives. If you thought going out to a concert would be a fun, non-political activity, you'd be wrong.