I've already mentioned the very last line of dialogue which really gets at the core of Stan's psychological nature: "Mister, I was born for it." That is, to be the "geek." That is symbolic of how at the base of his emotional being, Stan feels like an unlovable creature, due to his father's behavior toward Stan as a child.

So let me go with this side of dialogue from Pete shared with Stan:

When a man believes his own lies, starts believing that he has the power, he's got shuteye. Because now he believes it's all true. And people get hurt. Good, God-fearing people. And then you lie. You lie. And when the lies end, there it is. The face of God, staring at you straight. No matter where you turn. No man can outrun God, Stan.

These are the words of a prophet as they detail where Stan's journey is going to take him. Even when telling the truth - and let's assume Stan actually "hears" that truth - it won't change the trajectory of Stan's choices or psychological arc. The journey he takes, one of dissolution, is the one he needs to take. It is - in my language system - his Narrative Imperative.

Stan's lies get bigger ... and bigger ... and bigger ... until he is confronted with pulling off the Big Sting in the end. Which collapses under the weight of the emptiness within Stan's inner being. There is no there there ... other than the haunting specter of Stan's shadow, the gravitiational lure of his inner geek.