Late response here, but...
There was a time when Supernatural was entertaining, then there was a time when it was good for short laughs. Now it's just stupid.
And I'm not a Christian.
For the sake of constructiveness, I will at least say this: the screenwriters have absolutely no imagination whatsoever; I mean, ffs, couldn't they think of something better for dying and going to heaven ?!
Personally, I began to lose faith in the show when they introduced angels, especially Uriel, but there's no need to go into detail about that, it's pretty self-explanatory.
Well, Zooloo and I agree entirely on where this show ended up. I loved it for the first 4 seasons or so, then season 5 and onwards has been a snorefest all the way through.
I do admit that the moment I realized the kind of cosmology that Kripke has, the show lost all connections to real life. Now, you might complain here and say "It's not supposed to be real!". I know this, but usually fantasy movies at least deal with real questions that people have, using the fantasy as a vehicle for this. Supernatural's cosmology is illogical and increasingly irrelevant to my whole worldview.
So yeah. I suppose my faith makes me incompatible with it. A deist, deadbeat god, and a humanity that has better morality than anyone else. That's about as far from my conception of reality as one can get.
Of course, if I was in the position of Dean and Sam, I would act exactly as they do. But that doesn't make it a show that I can relate to.
They should've the angels out of it, and stayed at what they did best: folk-lore and badass ghost hunting!