Everyone believes your lies. No one believes you when you tell the truth. How would you use this power for good?
A wizard casts a spell on you. For a year, everyone except the Wizard believes you when you lie, but not when you tell the truth. She tells you that if you use this situation to make the world a better place she will grant you a super power of your choice with her magic.
You will be able to get a power commensurate with the amount of good you do. She will be the judge of both the power and the quality of your work. She is highly perceptive, insightful, and intelligent and can see the future consequences of your actions. She'll give you extra points for creativity since she's doing this because she's bored.
You have one year, at which time the spell will expire and you will be judged.
If you fail, the wizard will undo all your actions and wipe everyone's memory. Including yours.
What is your strategy for success?