I'm not sure how many Americans you all have met, but I have yet to meet enough arrogant and nationalist ones to consider it a stereotype
I lived in the USA for 3 years. I have not lived there for 10 years, but still keep in touch with and visit the friends I made there. Don't mistake patriotism for ego. Canada has a lot to be proud of, as does the US. The Amercians are just a little more vocal about it, and, as a Canadian who was basically an American for a while, have good reason.