At this encounter the general theme of the conversation was
human virtue, and most of the discussion centered upon the topic of
courage. Here Plato took the line that of all mankind the tyrant
possesses the smallest share of this quality, and then turning to the
subject of justice, he maintained that the life of the just is happy, while
the life of the unjust is full of misery. Dionysius would not hear out this
argument, since it implied a direct reproach to himself, and he grew
exasperated with the audience when he saw how much they admired
the speaker and were charmed by his doctrines. At last he lost his
temper and angrily demanded of Plato why he had come to Sicily.
Plato replied that he had come in search of a man of virtue; whereupon
Dionysius retorted, "Indeed! Then, by the gods, you do not seem to
have found one yet!"
-- Penguin Classics 1973