Ambition is like choler, which is an humour that maketh men active, earnest, full of alacrity, and stirring, if it be not stopped. But if it be stopped, and cannot have his way, it becometh adust, and thereby malign and venomous. So ambtitious men, if they find the way open to their rising, and still get forward, they are rather busy than dangerous; but if they be checked in their desires, they become secretly discontent and look upon men and matters with an evil eye, and are best pleased when things go backward, which is the worst property in a servant of a prince or state.

- Francis Bacon, The Essays, Penguin, London, 1985. p. 173.