The children now love luxury; they have bad manners, contempt for authority; they show disrespect for elders and love chatter in place of exercise. Children are now tyrants, not the servants of their households. They no longer rise when elders enter the room. They contradict their parents, chatter before company, gobble up dainties at the table, cross their legs, and tyrannize their teachers.
They [Young People] have exalted notions, because they have not been humbled by life or learned its necessary limitations; moreover, their hopeful disposition makes them think themselves equal to great things – and that means having exalted notions. They would always rather do noble deeds than useful ones: Their lives are regulated more by moral feeling than by reasoning – all their mistakes are in the direction of doing things excessively and vehemently. They overdo everything – they love too much, hate too much, and the same with everything else.
— Aristotle (~340 BC)
POV: bad parenting, “gobble up dainties” who put them there to begin with?
Is that a metaphor?
No. At the time, sitting attentively with your feet together was good manners. Crossing your legs would have been considered lax or sloven.