Oh, that's it. Dean's had it with this. She comes in when Dean is relaxing, when he's already trying to forget why he's worried about Sam in a more positive way than drinking, and getting on his ass about lying when she has no idea what sort of things have happened?

Not gonna fly.

"I'm willing to lie about whatever keeps me and Sam safe," Dean snarls after her. "Sorry you're too detached to give a rat's ass about anybody but yourself."