You may think you are completely insignificant in this world. But someone drinks coffee every morning from their favorite cup you gave them. Someone heard a song on the radio that reminded them of you. Someone read the book you recommended and plunged head first into it. Someone remembered your joke and smiled, returning home from work in the evening. Someone loves himself a little more, because you gave them a compliment.
Never think that you have no influence whatsoever. Your trace, which you leave behind with even a few good deeds, cannot be erased.