Apart from their NCOs I was never able to work out what rank Americans were. Privates, WOs and officers all looked the same to me. Of course, we Brits don't even salute Air Chief Marshals if we're not wearing our hats and we never wear a hat indoors. Americans are big on saluting and seem to salute everybody, everywhere all the time, hatless or not.
I was once saluted at fifty paces by a Gurkha sentry when the RAF first put rank badges on NCOs' epaulettes. He insisted on having it returned and I had to resort to a certain vocabulary I learned in Brats, to convince him I was a Sergeant.