(Corinthians:) They (Athenians) are revolutionary, equally quick in the conception and in the execution of every new plan; while you are conservative— careful only to keep what you have, originating nothing, and not acting even when action is most urgent.
They are bold beyond their strength; they run risks which prudence would condemn; and in the midst of misfortune they are full of hope. Whereas it is your nature, though strong, to act feebly; when your plans are most prudent, to distrust them; and when calamities come upon you, to think that you will never be delivered from them.
They are impetuous, and you are dilatory; they are always abroad, and you are always at home. For they hope to gain something by leaving their homes; but you are afraid that any new enterprise may imperil what you have already.
When conquerors, they pursue their victory to the utmost; when defeated, they fall back the least.
Their bodies they devote to their country as though they belonged to other men; their true self is their mind, which is most truly their own when employed in her service.
When they do not carry out an intention which they have formed, they seem to themselves to have sustained a personal bereavement; when an enterprise succeeds, they have gained a mere instalment of what is to come; but if they fail, they at once conceive new hopes and so fill up the void. With them alone to hope is to have, for they lose not a moment in the execution of an idea.
This is the lifelong task, full of danger and toil, which they are always imposing upon themselves. None enjoy their good things less, because they are always seeking for more. To do their duty is their only holiday, and they deem the quiet of inaction to be as disagreeable as the most tiresome business.
If a man should say of them, in a word, that they were born neither to have peace themselves nor to allow peace to other men, he would simply speak the truth.
(Book 1 Chapter 70.2-9)
Thucydides (History of the Peloponnesian War: Bk. 1-2)