The Sith Prophecy
He will remake [or rename] himself.
He will be balanced between peace and conflict.
He will win and break his chains.
He will strengthen himself through sacrifice.
He will know brotherhood.
He will strengthen himself through pain.
"The Sith who were famous for being bad, Jacen, were the way they were because they were badly damaged men or women to start with. Not because they were Sith, Usually, they were weak, or deluded, or greedy to begin with." --Lumiya
Lumiya: "After all, everything I tell you is a lie...Vergere. She said that, didn't she? When she was training you to be a Sith?"
Jacen: "She was training me to survive."
Lumiya: "Yes. To survive. Survival is a Sith trait. Jedi train themselves for self-sacrfice, for union with the Force, and they can afford to be suicidal, because there are so many of them. Sith train to survive."
"Here's the truth about the difference between Jedi and Sith. Both Jedi and Sith gravitate toward rule. But the Jedi believe it's contrary to their nature, so they create guildelines that are only supposed to govern their own actions...until the unevitable day when the secular governments fall so short of Jedi ideals that they feel they have to impose their own rules on others, to save them. That's what happened at the end of the Old Republic. But the rules they put together are strange, ascetic, not designed for ordinary people, and they can't be sustained as a form of governement.
"The Sith recognize from the start that they can choose to impose their rule on others...or not. If society is functioning well, a Sith doesn't have to act. [Darth] Vectivus didn't. If it's not, he should act. And since he knows that fixing a broken government is his mission, he can design a system of government that works, that is fair, orderly." --Lumiya
"Sith, like Jedi, have to determine the fates of others. Unlike Jedi, they know that sometimes this means sacrificing one so that twnenty may live." --Lumiya
"The Jedi find their balance through the abandonment of attachment. The Sith celebrate attachment...but find our balance in the deliberate, agonizing sacrifice of some of the things we love most. Only by that means can we retain our appreciation for loss, pain, mortality—those things that ordinary people experience." --Lumiya
Such a philosophy would allow the Sith to retain their passion...but pain would keep those passions in check. Sith like Palpatine had not followed this principle, had followed philosophies of gain and loss, and their greed had doomed them and everyone around them.