I have a good friend who has been caring for his elderly mother. She sits in a wheel chair, complains a lot, and requires constant attention — to the point of cleaning her up after regular bouts of diarrhea. What my friend and his wife are doing is heroic, virtue with a capital V. But it is hard to see how it is "world changing" as we normally think about such things. Such an act doesn't even change the mother's life, only makes it less miserable. It's not even "significant," by our usual calculation, but "merely" an act of love.
When we think of making a difference, we think about making the world a better place for the next generation, not taking care of people who have no future....As usual, Jesus turns this whole conversation on its head....His is an ethic that glorifies giving a mere cup of water to a thirsty soul (Matt. 10:42), praises the relatively worthless donation of an indigent widow (Mark 12:41-44), visits those who have disappeared from history, and honors the one who changes the diapers of the incontinent.