Eminem

It's about borderline personality disorder. There are 2 ways to interpret this interpretation - is Skylar Grey a person with BPD, the "she" Eminem refers to? Or is she another perspective of someone whose partner has BPD? In either case, Eminem's partner has BPD in this song. As someone whose (ex) partner had BPD, this song does a fantastic job of portraying the struggle of the person taken along for the ride.

"Now I'm the one thing You couldn't hate more But you're the one thing That I would die for"

The partner of a person with BPD often feels they would do anything for them, even when being strung along until something better comes along, as mentioned elsewhere in the song.

The "walking on eggshells" analogy is a good one - one never knows what will set the partner with BPD off. I feel the deepest part of the song is the doubt Eminem both feels toward his friends in the beginning, and later toward himself.

In life, no one truly teaches how to deal with a loved one's mental illness. If somehow art and music can help create awareness, that's great.