If you can't feed a hundred people, then feed just one.
Simple and to the point. It reminds us that one makes a difference and I believe that. How we treat one person at any time has an everlasting effect, like the ripples caused by a pebble thrown in the water.
It remind me of Mitch Albom's book "The Five People You Meet In Heaven". Some of the people he meets he barely remembers because they played a minor role in his life yet his action played a major role in theirs and he never knew it. It's the same lesson as in the Mother Teresa quote; every action no matter how small matters. It's not easy to live our lives that way but I think it's a good to be reminded.