The Dark Side of the Force is an aspect of the Force that responds to emotion. The path is considered a quicker, easier means to achieve power, but it responds at least as quickly to negative emotions (fear, anger, hate, etc.) as to positive emotions (love, joy, sympathy, etc.). Dark Side practitioners tend to be far more selfish than Light Side practitioners and far more willing to use the Force as a deadly weapon.
The Dark Side is sometimes considered unreliable, as its power may fail users unexpectedly (as it did when it provided Emperor Palpatine with the foresight to prepare an ambush for the Rebel Alliance, but failed to warn him about the possibility of his own death).
- "Strike me down with all of your hatred, and your journey towards the Dark Side will be complete."
- --Emperor Palpatine