Dean hated you. He despised you, even. You never really knew why, whether it was your happy demeanour, your voice, or even you in general. One day, Bobby asked you to help Dean during a hunt gone wrong, since you were close by. And you did, but you hurt yourself badly. Dean was unconscious when you went in and killed the monster, so when he woke up, and saw you, on the ground, grabbing unto your wound, his expression changed. He went right to you, analyzing your wound.