One type of person, whenever he does someone else a good turn, is quick in calculating the favour done to him. Another is not so quick to do this; but in himself he thinks about the other person as owing him something and is conscious of what he has done. A third is in a sense not even conscious of what he has done, but is like a vine which has produced grapes and looks for nothing more once it has produced its own fruit, like a horse which has run a race, a dog which has followed the scent, or a bee which has made its honey. A person who has done something good does not make a big fuss about it, but goes on to the next action, as a vine goes on to produce grapes again in season. So you should be one of those who do this without in a sense being aware of doing so. – Marcus Aurelius, Meditations, 5.6