Disinterest in displacing others, an American props his feet upon a public seat.
My first thought when I saw the feet on the chair was "definitely American."
I then figured the feet belonged to someone who lived in NYC, because we're all collectively about every individual acting independently and rationally according to self-interest, behaving contrary to the best interests of the whole group by depleting some common resource. He could also just be a millennial, (which are awful everywhere, I hear) not so much intentionally selfish but inadvertently inconveniencing others due to their obliviousness, stupidity.
His passport, which he displayed to the flight attendant who came over a moment later to pre-board us, confirmed he was American.