I'm very suspicious of the bar girl. I don't believe she is entirely what she seems. I watch this show!

And there's going to be fallout from demons spreading the word to the hunting community

This. With Sam having separated himself from his family (Dean and Bobby), demons are cutting Sam from the herd--isolating him. At the same time, Lucifer is hacking away at Sam's fragile psyche, reinforcing Sam's sense that he can't escape the fate to which his mother doomed him. JP's performance was heartbreaking.

I'm guessing the blood that managed to get into Sam's system opened a communication link with Lucifer?

More semi-incoherent thoughts:

I don't think you can deny that Dean, for whatever reason, has always been way too tied to his family. Some of that's his upbringing, some of that's his own damage.

Oh hell no, I don't disagree. John has a lot to answer for (or he would if he weren't, you know, dead). Added to it is Dean's "own damage." I think he's largely gotten a pass in the pieces of fandom that I've read for things that he needs to take responsibility for ... his unquestioning obedience to John's orders to the point of self-abnegation is a large one. Martyrdom isn't an attractive or healthy character trait. And I've always felt that Dean resented Sam leaving for Sanford at least partly because Sam was strong enough to make the decision and act on it, and Dean... wasn't. Either that or Dean wanted to be a hunter, he truly believes in the value of what he does to help people, and it is indeed the life he wants to live. In which case, his staying in that life wasn't a sacrifice. And he still bitches at Sam for daring to have chosen something different.

I think the writers don't always show Dean to advantage. I saw a lot of it tonight. I know a big part of his character is supposed to be him being a smartass, but showing deference to all-powerful beings isn't necessarily a sign of weakness. (I'm always driven crazy by characters who would be smarter if they pretended to go along with the bad guy until they're in a stronger position to fight back, but instead they make wisecracks and let the bad guy know right away that they are in opposition. And Dean does that ALL the time.) He's smart, inventive, a skilled and strong hunter, capable of great focus and determination. Last week's episode showcased him well. Tonight's, not so much.

Oh, Sam.

I'm of the opinion that Sam's blood isn't so tainted that he can't be a vessel for Michael, too. Not a spoiler, just speculation.

Is Sam the only YED tainted kid still living? Is that what makes him a Lucifer-vessel? Or is it symmetry with Dean being a Michael-vessel?

I am not happy with Dean's whole "yippee skippy" I'm so happy now that I don't have to deal with my brother attitude

He's lying to himself so hard, though. And doing not a great job of it.

I don't think I understood part of this ep. Why was what Castiel said to the hooker so funny to Dean and so upsetting to the hooker? Is there some Hooker daddy issue thing I don't understand? Why did Dean keep bringing up the post office? Why did the writers forget that Dean has said he doesn't pay for sex?

I don't think Dean was going to pay for his own sex, just Cas's. Castiel started talking to his hooker about her daddy issues, and it freaked her out, and that and the escape from the looming bouncers seems to have cracked Dean up. I think the absurdity of the premise kinda hit home for him.

Plus they weren't running away from monsters or demons. Just a few humans. It was "normal" compared to everything else.

I don't think you can deny that Dean, for whatever reason, has always been way too tied to his family. Some of that's his upbringing, some of that's his own damage. I'm not going to begrudge him feeling a little bit freed right now - especially since it's about 80% bullshit.

Very much this. That 80% is all "brave little toaster" posturing.

I think the absurdity of the premise kinda hit home for him.

This. And what Suzi said.