The narrator in "The Yellow Wallpaper" is a sensitive woman who has been consigned to permanent bed rest in an isolated house in the countryside by her husband. It is clear that in spite of the love she has for her husband, this decision of his and his diagnosis of what is precisely troubling his wife is something that the narrator disagrees with strongly:
I sometimes fancy that in my condition, if I had less opposition and more society and stimulus--but John says the very worst thing I can do is to think about my condition, and I confess it always makes me feel bad.
The narrator's own thoughts and opinions are ignored and disregarded by her husband, who clearly feels he knows better. The narrator is thus left to write in secret (as this is a forbidden activity) and also, in her time left in the bedroom, she comes to obsess and focus on the yellow wallpaper, and to project herself and her own position onto it:
I didn't realise for a long time what the thing was teh showed behind, that dim sub-pattern, but now I am quite sure it is a woman.
The narrator imagines a woman trapped behind the bars of the yellow wallpaper, which of course symbolises herself and her own intellectual and personal imprisonment. At the end of the story, she literally becomes this woman by walking around the edge of the room.
Paul, in "The Rocking-Horse Winner," on the other hand, is a young boy who is desperate to gain the affection and love of his mother. It is her continual and grasping desire to gain more money that causes him to embark on a quest to gain luck so that he can win money for her. It is this that leads him to start riding frantically on the rocking horse:
He went off by himself, vaguely, in a childish way, seeking for the clue to "luck." Absorbed, taking no heed of other people, he went about with a sort of stealth, seeking inwardly for luck. He wanted luck, he wanted it, he wanted it. When the two girls were playing dolls in the nursery, he would sit on his big rocking horse, charging madly into space, with a frenzy that made the little girls peer at him uneasily. Wildly the horse careered, the waving dark hair of the boy tossed, his eyes had a strange glare in them. The little girls dared not speak to him.
It is this search for luck, and through luck for money, that Paul embarks upon that actually leads to his death, as whatever money he gains is shown to be never enough to satisfy the materialism and greed of his mother.
Both characters therefore are driven into worsening conditions thanks to the relation that they have with a key individual in their lives.