Things that go against how Americans live, especially historically.
ie professionalism is being fake and America hates liars. Paperwork is anti-fighting and Americans love fighting and watching it. Cussing is freedom of speech and there's lots of sailors in america. Feelings tend to be absent of reason and logic and in america we believe in evidence not defense.
So some un-American immigrant was offended today that i called him a little communist propaganda machine. Response: Good to to hear you're taking the offensive, all these "poor me's" on the defense are un-American.