When he is walking up fifth avenue what pessimistic remark does holden make?

While walking up Fifth Avenue, Holden Caulfield expresses his disdain for the phoniness of the people around him, remarking about how superficial and insincere he finds them. He feels alienated and disconnected, observing how people seem to be pretentious and overly concerned with appearances. This reflects his broader struggle with the adult world and his longing for authenticity.