Let's be clear: Background Pony is not a happy fic. It is not a story that makes everything happy at the end of the chapter. It will make you very sadface.
If you don't like sadface, do not read Background Pony.
If you can handle sadface and are okay with philosophy, then Background Pony might vaguely interest you. If you ENJOY philosophy, Background Pony will blow your mind.
Background Pony deals, to an almost cosmically brilliant degree, with the intricate consequences of a single, fundamental shift. Lyra's curse in BP is so simple, yet so hauntingly painful that it strikes, to a greater or lesser degree, into the soul of any reader and demonstrates the important things about life through sheer vibrancy of dictation, characterization, imagery, and empathy.
It is a story about non-existence, about the intricate necessity to make an imprint on the world and how unimportant that imprint ultimately is. It is a paradox, and Background Pony demonstrates how both are necessary to be truly, definably alive in this world. Lyra's attempts to be remembered, her sad acceptance, then placid calm progression forward, are representative of the need for humans to be memorable, that moment when we realize we aren't, and the strength of character it takes to not give up and make a way where none apparently exists.
Are you up to such a task, dear reader? For while many of use may be fans of Lyra Heartstrings, not many of us would be able to persevere as she has.