Why does Johnny feel renewed at the end of the story ?

By this point in the story, Johnny has come full circle. He no longer shies away from physical pain or work, as he did in the early chapters set at the Laphams’ house. He is also able to think rationally about his behavior rather than surrendering to his first impulses; he is stoic about Rab’s death and agrees to the operation because he knows that doing these things will be better in the long run, even if they are difficult now.