I just watched last week's Supernatural, "Dark Side Of The Moon" a second time, so I could hear Dean say again that Heaven "isn't Nirvana - it's the Matrix." How can paradise be bad, when there's beer? Spoilers ahead!
Unlike other shows that have dealt with devils and gods - like, say, Buffy - Supernatural has given us a very clear sense of what Heaven is really like. Hell remains an abstract blaze of fire and pain, but Heaven is a concrete place where you can drive down an asphalt road, visit a dive bar, and attempt to flee from very angry archangels through the forest. This is one of the many crazily audacious things that I love about this series.
The brothers find themselves in Heaven after a couple of Hunters shoot them in their beds for starting up the Apocalypse. Apparently, a bunch of Hunters have been trying to assassinate them, and these are just the first who were lucky enough to catch the Winchesters asleep.
Turns out that Heaven is drawn from everybody's happiest memories, and unfortunately Castiel can only talk to the boys via some kind of secret back channel on old-fashioned radios and televisions. So their only guidance is the radio in Dean's car telling them to follow "the road." Other people see tunnels and rivers, but of course Dean sees two-lane blacktop. Before they get ported back into their meatsacks, Cas is hoping the brothers can track down the angel Joshua, who talks to God, so they can find out what the hell is up with this whole letting Armageddon happen thing.
As the boys wander through Heaven, we soon discover that Dean's happiest memories involve making Sam happy, and seeing their mother again (there's a great scene where Dean's wardrobe goes down memory lane with him, and he finds himself dressed a t-shirt says "I wuv hugs"). Tragically, Sam's happiest memories are all of times when he left the family behind by running away or going off to college. So the brothers start arguing about emo shit like family and whether Sam truly loves Dean, right there in the middle of Heaven's highway, which gives dicky archangel Zachariah a chance to track them down.
Luckily, they're rescued by their old buddy Ash, who helpfully explains Heaven to them (see clip - as Ash puts it, it's a "whole buttload" of individual heavens, one for every person). Ash even shows off his "angel police scanner," which lets him figure out what the angels are up to. Sounds like Ash is the right guy to know in Heaven.
Dean gets into a pretty interesting debate with another old friend of theirs - a witch they killed accidentally - who says that Armageddon might not be so bad if everybody winds up in Heaven. "I'm happy here," she says. And that's when Dean tells her that everybody being trapped in their own individual heavens is "lonely," then lays down my favorite line of the episode: "That's not nirvana - that's the Matrix." It's true. Who wants to be in Heaven all by themselves?
Unfortunately, it looks like that's God's plan. Eventually the boys meet Joshua. He shows up just as they are getting chewed out by Zachariah, who is explaining that the main reason he hates the Winchesters is that their recalcitrance means he's now no longer "employee of the month" among the angels.
Joshua whisks them away to the Garden, and explains that God is currently on Earth and has a message for the boys: "Back off." God knows that the End Times are underway, but apparently it just isn't relevant to him. When the Winchesters start asking how God could just sit back and let this happen, Joshua replies, "Why does he allow evil to happen? You could drive yourself crazy asking questions like that." Apparently, after rescuing the boys from Lucifer once (when he put them on a plane away from danger), and "giving them a place in Heaven," God is done with interventions.
Back inside their meatsacks, Sam and Dean break the news to Castiel about God's lack of interest in the Appocalypse. The angel is completely distraught, and refers to God as someone he "once believed in." So everybody is having a faith crisis now. Worst of all, Dean no longer believes in Sam (again). He's still so bummed about Sam's visions of Heaven that he walks out the door of their hotel room, and drops the God-finding charm Sam once gave him in the trash. Dean is such a drama queen.
I don't believe for a minute that God is going to sit this one out, though. He already rescued the boys from Lucifer so that they could live on Earth rather than in Heaven. Why would he do that if he wasn't just a teeny bit invested in the humans winning out over the angels and demons who want to turn the planet into a giant toxic battleground?