"There is a common misconception that the Sith access the Force through evil or that being a Sith Lord automatically means that you are evil. This is not true. Any extreme emotion can access the Force. The essence of the Sith's power is in passion, not evil. Passion can take the form of joy or love as well as anger or hatred. Sith are typically evil in that they are often blinded by their passion or corrupted by the power granted to them by the Force.
This plays into the second major difference between the Jedi and the Sith. The Sith believe the Force is a tool to be used and that the power in and of itself is justification enough for their actions. In short, they believe they can do anything they want simply because they have the power to do so.
Sound like anybody we know?"