I definitely took the scene at the end between Ruby and Sam to be her gloating over Sam. He could have ganked demons at any point if he'd wanted to/worked on it but she's provided the demon!blood and altered his sense of reality. Drug addicts are not known for their feats of logic or their insightful thinking. I think there was a pretty huge leap between moving a piece of furniture under duress and burning demons out of their victims with not enough reason outside of the demon blood but...HANDWAVE!

You know what? Now that I"m verbally rambling all over your LJ, I'm thinking about the way Jake Talley's talents blossomed once he'd said yes to the YED. Maybe there *is* some consistency there? He suddenly became powerful, getting all sorts of abilities Sam never had. So maybe if Sam had ever truly given in, stopped trying to use his powers for good, he'd have seen a similar leap? Just thinking out loud.

I think what didn't make sense was Sam having to drink gallons of demon blood to be a vessel. Don't think Nick did and Sam was supposed to be Lucifer's true vessel so that he wouldn't burn through his meat suit like with Nick. Wish they hadn't felt the need to go there. *shrug*