@ powerfulone1987 - Sam avoiding the hug struck me as odd too at first, but I'm pretty sure it was just because Sam didn't call Castiel for a reunion. He called in order to get answers. He knew Dean and Bobby were hiding something from him, so he called Cas to try and figure out what specifically was up. He was so determined to get his answers as well that he couldn't treat the arrival of the angel as a happy reunion just yet. Not until he knew that Cas wasn't going to hide something from him as well.
As for the episode itself, I loved it, but I was put off a bit by the dragons and Mother. Not the mythology itself, but their appearance as already mentioned. Since we know that these dragons have actual dragon forms, I didn't think it made a whole lot of sense for them to also have humanoid forms. I would have been fine with them just continuing to do what they had been doing with the episode... a vague dragon silhouette, the sound of wings... They did it with the Lamia back in "Weekend at Bobby's" (though it did annoy me a little in that episode because we really didn't see ANY of it, unlike what little bits we got of the dragons throughout the first half of the episode).
And then Mother herself wasn't all that menacing. I'm tired of the whole vessel/possession plot lines. I understand it for the angels, demons, and ghosts to some extent. The spiritual need physical vessels in order to more properly interact with the physical world. So why does the Mother of all monsters (things that are already physical) need another's body? Is the Mother herself not physical? All of the popular lore on the mother of all creatures portrays the mother as a physical monster herself. Did Supernatural change that part of the lore? Or are they going in the direction of, "Way back when, the Mother was killed and her soul went to Purgatory. The monsters have now resurrected her soul, but without her old body they had to stick her soul into a new one"?
I could live with the latter option, though I still prefer the notion from the earlier seasons that monsters don't have souls. They just cease to exist when they die, and Purgatory is just a bedtime story for the monsters to assure them of an afterlife that isn't really there. In that instance, the Purgatory that was opened during this episode could just be the realm where all monsters were originally born before they entered into the physical world of Earth. Unfortunately, that option (while keeping the lore true to itself from earlier seasons) would mean that the Mother is indeed a spiritual creature who had to take on a physical body in order to cross over, and that just doesn't make as much sense.
Top that off with the fact that the white-eyed black guy from the promos looks more threatening than Mother right now (and Mother doesn't have the same creepy/threatening air about her like Lilith did (even the child version)), and I'm just a little underwhelmed with her right now.
Those two things aside though, awesome episode. I would have rated it higher than the reviewer.
EDIT: Also, where's the Colt? According to Lucifer there's only 5 things that it can't kill. I doubt dragons are on that list. Why didn't they use the Colt rather than looking for a dragon-slaying sword? (And if the Colt is still lost, why haven't they tried looking for it again yet?)