It is a true observation of ancient writers, that as men are apt to be cast down by adversity, so they, are easily satiated with prosperity, and that joy and grief produce the same effects. For whenever men are not obliged by necessity to fight they fight from ambition, which is so powerful a passion in the human breast that however high we reach we are never satisfied.
Niccolo MachiavelliThe Romans never allowed a trouble spot to remain simply to avoid going to war over it, because they knew that wars don't just go away, they are only postponed to someone else's advantage. Therefore, they made war with Philip and Antiochus in Greece, in order not to have to fight them in Italy... They never went by that saying which you constantly hear from the wiseacres of our day, that time heals all things. They trusted rather their own character and prudence- knowing perfectly well that time contains the seeds of all things, good as well as bad.
Niccolo Machiavelli