what was the irony of the carve oak that the author's friend experienced in Kingston?

J. uses this as an occasion to meditate on how people always want what they cannot have, and do not want the things they do have. He recalls a former classmate named Stivvings, who was dedicated to his studies but was often too sick to complete his work. Meanwhile, the other boys hoped to get sick to avoid schoolwork, and became sick only when vacation came around.