What did Johnny realize at the barn dance?

When Johnny is at the barn dance at the Grandsire's big barn, he forgets about his deformed hand. The girls he dances with take his hand, and they don't seem to notice that his hand is misshaped. The girls' behavior is different from that of the Boston girls, who won't touch his hand and regard his hand as revolting. Later, Rab tells him that Johnny makes people think his hand is disgusting, as he always hides his hand in his pocket and takes it out as if it were hideous. If Johnny forgets that his hand is misshapen, he conveys a stronger and more confident sense of himself to others. Johnny realizes that the way other people see him has a great deal to do with the way he presents himself to the world.