Remember this for a moment.

Dean: Well, I'm probably going to die tomorrow

Cas: I'll go with you.

BUT WHAT IF INSTEAD,

Dean: Well, I'm probably gonna die tomorrow

Cas:........

Cas: Well, last night on Earth. Any plans?

Dean: *remembers this*

Dean: I just thought I'd just sit here quietly.

Cas: Come on, anything? Booze? Women? Me?

Dean: I- wait.

Cas:......

Dean:......

Dean: You. Definitely you.