First to end one woman's ordeal with the rest-cure
And secondly the doctor who suggested the rest-cure to her changed his practices after reading it. think about that. This story, written by a woman during a time that women had little to no power over their lives, got a physician to change his practices in regards to women
Nightmare Fuel: A case has been made that the "Yellow Wallpaper" that the narrator is ripping off of the walls at the end is her own skin.
In the story itself, the narrator ends up completely insane and creeping in circles around the room. Eventually her husband finds her like this and faints from the shock. She simply continues pacing, walking over his limp body and narrating this in the most calm way possible, as if there weren't anything strange about it.
On a meta-level, H.P. Lovecraft considered this an excellent depiction of horror and madness. Think about that.