Dean and Sam in “Unfinished Business”

Dean

You know what, there's a ton of lore on unicorns, too. In fact, I hear that they they ride on silver moonbeams, and they shoot rainbows out of their ass!

Sam

Wait. There's no such thing as unicorns?

Dean

That's cute. I'm just saying, man, there’s some legends that you just... you file under "Bull Crap".

Sam

And you got angels on the "Bull Crap" list?

Dean

Yep.

Sam

Why?

Dean

Because I've never seen one.

Sam

So what?

Dean

So, I believe in what I can see.

Sam

Dean, you and I have seen things most people couldn't even dream about.

Dean

Exactly, with our own eyes. That's hard proof, okay? But in all this time, I have never seen anything that looks like an angel. And don't you think that if they existed, that we would have crossed paths with them, or at least know someone that crossed paths with them? No. This is a demon or a spirit. You know? They find people a few fries short of a Happy Meal and they trick 'em into killing these randoms.