A married couple were enjoying a luxury South Sea cruise until their liner was shipwrecked and they were washed ashore on a desert island, the only survivors. Day after day, they looked hopefully out to sea in the hope of spotting a passing vessel but none came. As boredom set in, they started to think about their home back in Arizona. The wife asked: "Did you remember to pay the final instalment on the Chevrolet before we came away?" "No, honey, I clean forgot. Sorry." "Did you remember to pay …