Dean had never really maintained a relationship for very long. He'd dated quite a bit when he was younger, but after a while, he stopped putting out the effort, and instead focused his energy on one night stands,, in whatever town he happened to be rolling through. Faith was different, though; she was the one he kept going back to. She wasn't like the usual suspects; she was street smart, and she lived the life. She was a slayer, not a hunter, but in the end it came down to the same thing; they both fought against evil, no matter how nasty it turned out to be. Faith understood his restlessness in a way no one but Dad and Sam ever could, and she accepted it as part of who he was. Faith never tried to make him be or act like something he wasn't.
He fell in to step beside her, and swung out wide to jog around to the driver's side of the Impala. He wasn't the kind of guy to open the car door for her, not even on her birthday. That would be weird for both of them.