The Glimpses of the Moon by Edith Wharton

BUT there were necessary accommodations, there always had been; Nick in old times, had been the first to own it. How they had laughed at the Perpendicular People, the people who went by on the other side (since you couldn't be a good Samaritan without stooping over and poking into heaps of you didn't know what)! And now Nick had suddenly become perpendicular.

Susy, that evening, at the head of the dinner table, saw -- in the breaks between her scudding thoughts -- the nauseatingly familiar faces of the people she called her friends: Strefford, Fred Gillow, a giggling fool of a young Breckenridge, of their New York group, who had arrived that day, and Prince Nerone Altineri, Ursula's Prince, who, in Ursula's absence at a tiresome cure, had, quite simply and naturally, preferred to join her husband at Venice. Susy looked from one to the other of them, as if with newly-opened eyes, and wondered what life would be like with no faces but such as theirs to furnish it.