"There's more to it than that," Sam insists.

"She worked with me, okay? Helped me develop my abilities, so that I could take down demons. So that I could take down Lilith, when we found her."

There's no need to mention how she helped him, he reasons. Dean doesn't need to know about his drinking demon blood. Besides, it's not like he's going to keep doing that-- right? Right.

A beat.

"And then one day, we did."