I do hope that I effect positive change. However, I wonder if there is a better mindset. Maybe we are better off wondering about the nature of ourselves rather than the effect we have upon others? Not that I don't think that making a difference in people's lives isn't important, but like your piece addresses, it is such a nebulous measure. If we are looking for evidence of our good or value in others, we might be making a simple situation into a complex one.

You were doing good teaching those that needed it. The action was good, regardless of the response you could measure. You were a positive force.