When their father comes home with ammo instead of food, Dean becomes furious.
It's the way their father operates, the way he's always been. And as the old saying goes, you can't teach an old dog new tricks, but sometimes Dean wanted to pond the reality into that old dog's skull.
But because he's a good son, he doesn't make a sound as their father drops boxes of ammo on the table instead of bread and butter. Instead he simply goes out himself, lifts someone's wallet then buys food for the three of them.
When he comes home to Sam staring at the door because hunger won't let him sleep, Dean still doesn't allow his anger to control him. Instead he simply gives Sam the food, encouraging him to eat most of his own share.
But when he's alone, Sammy fast asleep on the other side of his bed, their father snoring away on the bed next over, he allows the anger to swell over.
Hot tears stream down his face, his finger nails bit into the flesh at his palm.
He knows he's stuck in this never-ending horror show. He knows his father is never going to bring home food, he knows the old dog will never learn.
And he knows he'll always be stuck in the same pattern. Because he's a good son who won't leave, he's a good son who will take care of everything his father won't.
He's a good son, but sometimes, he wishes he wasn't.