This quote is from Jane Goodall: What you do makes a difference, and you have to decide what kind of difference you want to make.
What kind of difference will you make today? Will you offer a friendly smile or a frown? Will you talk about what's great in your life or talk about problems and what's wrong with the world? Even these seemingly small choices DO make a difference, not only in how you feel, but how those around you are affected.
We don't have to be Mother Teresa to make a difference. We do it by doing what comes naturally for us. Sometimes it's SO natural, it doesn't seem to make a difference. Here's an example from my life. I'm a natural organizer, especially of events. Last Sunday I organized a trip to Kansas City for three friends and myself. We went to a morning service, lunch with several friends, and then to the Royals game, in a rented car no less. We had a great day! While I dearly love the friends that went with me, I know that if any of them had had to organize the adventure, it would not have happened. That sort of effort just doesn't "float their boats." So my willingness to organize made a great difference, and it was easy for me.
Consider your choices for making a difference. Go do it!