Ruby followed him into the bar marvelling that once again she was following Sam Winchester, Azazel, Lilith and now Alastair, they'd all laughed at her faith in him, insulted it. Told her she was little more than his pet demon.
But Ruby knew Sam. Even intimately. She knew how to break him down to build him up again. And thats what the little skirmish had been, Sam needed someone to challenge him, to rile him up, get the anger out. And that someone was her.
"You me and alley walls Sam, People are gonna start talking" she joked, ordering her own beer and paying for both.