Dean: Hey Cas did you know what horrors iv'e done in hell?
Cas looks at Dean all serious and tilts his head slightly.
Cas: No Dean tell me?
Dean: No I cant Cas you will never look at me the same again.
Cas: Dean I love you so much and I defied heaven for you, nothing you say could make me leave you.
Dean: I tortured Hitler and he was wearing a French maid outfit and I was shoving a pineapple up his ass.
And after hearing this revelation Cas went backto heaven never to return to earth.