in the supernatural that exists in my mind, the fact that sam and dean were created as the perfect vessels of the devil and an archangel makes them not totally human. there's a residual darkness and light inside them, respectively. sam especially so, after being fed demon's blood when he was a baby. it just comes up in tiny subtle ways so no one realizes there's something wrong with them
sam's ears always ring when he prays (he thinks it's a sign god is listening). rosaries feel peculiarly warm in his hands but he holds them tight anyway. chanting exorcisms leaves him lightheaded. he brittles any plant under his care no matter how many botanical books he reads. john jokes about how his weird drawings used to scare his preschool teachers but sam has no memory of making them. being inside devil's traps feels a bit like walking through water. he has always had a talent for making people and animals trust him, follow him - entranced like moths to a flame
dean on the other hand... there's an aura around him. he shines from within. people can feel it even if they can't put their finger on why he's just so charming. he wonders why he feels almost sleepy whenever he enters a church, he dislikes being so calm and unguarded. he unknowingly interferes with certain technology and makes it malfunction, like an overvoltage. babies love him but animals seem restless in his presence. when he's taking care of a wounded or ill person they heal a little bit faster but no one notices. reading enochian out loud gives him goosebumps. he thinks holy water tastes really good to everyone else too
you are sam winchester and everyone you love ends up dead because of you. your mother burns on the ceiling. your girlfriend burns on the ceiling. your college friends were puppets planted there for you. the people underneath the demons are long gone. your brother stabs your childhood friend. you get reunited with an old flame. she chokes in front of you. a gift to you. a message to you. you are responsible for your loved ones dying. you meet a hunter and she gives you hope that you could build something real and lasting, but she is killed and you know it was your fault. she would have been fine if she hadn't met you. she comes back and gets taken away again. you're destined to kill the one person who's ever understood you in your entirety with no judgment. you still think about jessica. your hell is right here you are cursed to kill and kill and kill.
you are dean winchester and your loved ones keep killing themselves for you. they die and they die and they die and it's all for you. not just because of but for you. offerings of devotion that make you want to repay the favor but you keep springing back up like a grotesque clown in a box. your curse is to keep on living and living, carrying them within you. an altar stained with their sacrifice. an obscene fire sustained against your will by the corpses of your loved ones.
look at him. if in the pilot dean had straight up chloroformed, abducted, and chained him to the passenger seat of the impala, I would've defended him. it would've been the most logical reaction