This quote is telling us that our actions have an effect, and it is up to us to decide what kind of effect we want our actions to have. In other words, no matter what we do, our choices will have an impact on the world around us and it is important that we make the effort to be mindful of the results of our decisions and to make sure that we are making the best choices for ourselves and for others. The kind of difference we make is completely up to us.