What contribution might I be making to the world without even knowing it?

I suppose it would be ideal if we always knew our impacts, and yet I am not unhappy with my ignorance. Theoretically something I say or do quite unconsciously can be seen or overheard by some passerby and this somehow triggers in them a decision or conviction that changes their life, for better or worse. I know from experience that something I have said or done with the very best intentions disappointingly later turns out to have had quite the opposite effect. So that even having the right intentions doesn’t guarantee positive outcomes down the line. Perhaps it is as simple as putting what effort I do have into working on being precisely who I am, and letting the chips fall where they may.