The beginning scene with Sam and Dean in the bar played out exactly as I would have written it myself. It's spooky, I totally pictured pretty much that same conversation after the previous ep!! Ruby had to spell things out for Dean - that he would become a demon, that she couldn't save him, etc - but I think Sam figured it all out on his own once Ruby dropped the bomb that she'd once been human. That's why it was Dean Ruby appeared to at the end rather than Sam... Sam didn't need to be told. I didn't think the writers would actually explain that, or at least not so soon, so I was pleasantly surprised when they did.