Balance of Light and Shadow
One of the main concepts in witchcraft is that of the duality of the universe. Nothing is purely good or purely bad. All aspects reflect the duality of nature. People bear these aspects of duality. We have the "light" traits (kindness, intellect, generosity) that we readily acknowledge and present to others. We also have our "dark" side as well. These are the traits (such as jealousy, anger, and greed) that we hold from public view and many times neglect to acknowledge. Again, nothing is purely good or bad. With that in mind, we can think of our dark traits as a power that balances our lives and promote positive change. Jealousy can be a motivator to strive for better. Anger can be the motivator to change or prevent bad situations. Light a black and a white candle, and say:
Goddess of darkness, Goddess of light,
Balance of duality I accept as my right.
Focus on your traits, both in the light and dark realms. Focus on the positive messages that both have for you.
(This reminds me of a Star Trek episode when Capt Kirk was split in half by the transporter machine. His dark shadow side and his light side. This episode showed how both sides make the whole person and how you need both the light and the dark aspects of your personality. That episode really demonstrated this concept really well.)
Enemy Within - Star Trek