Remember why the Sith are more powerful than the Jedi, Sidious: because we are not afraid to feel. We embrace the spectrum of emotions, from the heights of transcendent joy to the depths of hatred and despair.
"Uncertainty is the first step toward self-determination," Plagueis said. "Courage comes next."
The power of the dark side is an illness no true Sith would wish to be cured of.
Plagueis extended his left hand to touch him on the crown of the head. "Then it is done. From this day forward, the truth of you, now and forever more, will be Sidious."
We are all two-faced beings, divided by the Force and fated for eternity to search out our hidden identities.
Rarely did events play out as imagined, in any case. The order of future events was transient. In the same way that the past was reconfigured by selective memory, future events, too, were moving targets. One could only act on instinct, grab hold of an intuited perfect moment, and spring into action.
To say that the Force works in mysterious ways is to admit one's ignorance, for any mystery can be solved through the application of knowledge and unrelenting effort.
Tell me what you regard as your greatest strength, so I will know how best to undermine you; tell me of your greatest fear, so I will know which I must force you to face; tell me what you cherish most, so I will know what to take from you; and tell me what you crave, so that I might deny you.
Star Wars Books - Dark Lord: The Rise of Darth Vader
Evil? What is that? ...You said you were death itself. Are you evil, then, or are you simply stronger and more awake than others? Who gives more shape to sentient history: the good, who adhere to the tried and true, or those who seek to rouse beings from their stupor and lead them to glory? A storm you are, but a much needed one, to wash away the old and complacent and prune the galaxy of deadweight.
A Jedi sufficiently strong in the Force can be trained to produce a facsimile, but not true Sith lightning, which, unabated, has the power not only to incapacitate or kill, but to physically transform the victim. Force lightning requires strength of a sort only a Sith can command because we accept consequence and reject compassion. To do so requires a thirst for power that is not easily satisfied. The Force tries to resist the callings of ravenous spirits; therefore it must be broken and made a beast of burden. It must be made to answer to one's will.