History of the Peloponnesian War

And whenever they have conceived a plan but fail to carry it to fulfilment, they think themselves robbed of a possession of their own; and whenever they go after a thing and obtain it, they consider that they have accomplished but little in comparison with what the future has in store for them ; but if it so happens that they try a thing and fail, they form new hopes instead and thus make up the loss.

For with them alone is it the same thing to hope for and to attain when once they conceive a plan, for the reason that they swiftly undertake whatever they determine upon. In this way they toil, with hardships and dangers, all their life long; and least of all men they enjoy what they have because they are always seeking more, because they think their only holiday is to do their duty, and because they regard untroubled peace as a far greater calamity than laborious activity.