The look Caroline shot him spoke of true belief in his words. Right.

"Um, or you're being a complete bitch because I had a conversation with a friend during which I kissed him on the cheek because he's like, four hundred times nicer to me than anyone else on this planet. Not that I should ever have to explain myself to you, but I don't know, maybe I'm just taking a page from Bod's book and trying the whole nice thing for the day. I promise I won't tomorrow."

Not that Caroline thought she'd see Nathan the next day just based on his attitude.