The event where they got the paw conveys the theme because the mans first two wishes were so bad that, his last wish was to die.
Another event that conveys the theme was the family wished for $200 and got the money but also got a result of their son dying.
They wished for their son back but they didn't know what would come out of it. They didn't know if he would come back in the same body or as himself. So at the end they wished again for him to be dead.