The donkey problem

 A young boy and his father go on a long journey with their donkey. At first, the boy and his father both walk. They meet some people on the road who laugh at them. "Your donkey is very smart! He makes you walk. Soon he will ask you to carry him!"

     Next, the young boy rides on the donkey and the father walks. They meet some people who shake their heads in shock. They say, "What a selfish boy you are to ride the donkey while your old father walks! Shame on you!"
     Next, the father rides the donkey and the
boy walks. They meet some people who shake their heads in shock. They say, "What a terrible father you are to ride the donkey while your little son walks! Shame on you!"
     Next, both the father and the son ride the donkey. They meet some people who shake their heads in shock! They say, "What terrible people you are to both ride such a small, tired donkey! Shame on you!"
     Help! What should the father and son do?