Pure

You want a silver bullet.  Actually, before you want a silver bullet, you want a werewolf.  You want evil in your life so that you can kill that evil.  Actually, before you kill that evil you want to project all your evil into that evil so that you're good.  Yes.  You just want to be right and that requires that something else be wrong.  You just want to be 100% right and that requires that someone be 100% wrong.

There will be a moment, as your silver bullet pierces the werewolf's heart that good will win and evil will lose.  There will then be that moment, the one that follows the triumph in which the dead werewolf changes into a dead human and who were they?

Were they pure evil?  Did you kill them or the werewolf?  What is good now that evil is dead?  Is there another evil, another pure evil to define you?  Should you have chained the evil deep inside the center of the earth, hidden it away and only told stories about it, thus keeping it alive but away so that you can stay pure and good and it can stay corrupt and evil yet it can not touch you?

What if the problem of good in the world is equally as troubling as the problem of evil?  What if the real problem isn't the chicken and the egg but instead the werewolf and the silver bullet?