You've known Sam since you were both kids. Your father was a hunter and was close with John Winchester. That's how you knew Sam and Dean. You grew up into the hunting life as well. You and Sam had always been close. You were two years younger than him.
Recently, Dean just got back from Hell after four months. You Sam and Dean were now back together hunting. But, you and Dean found out the Sam was working with Ruby... and... well... guzzling demon blood. Yikes.
One night, Dean is out with some one night stand, leaving you and Sam alone in the motel room. He says he needs to go out to get some air, but you know better. He's going to visit Ruby, and you are not having it...
"Seriously, will you drop it? I'm just getting some fresh air. Nothing more." Sam snapped back as he shrugged on his green denim jacket.