Julie is the Juliet to R's Romeo. When R first sees her, he describes her eyes as "classic novels and poetry" (1.2.35). We all know Romeo was prone to bouts of poetry whenever in the presence of Juliet. And Julie the wine snob prefers Cabernet to Pinot Grigio, so she goes by "Julie Cabernet" sometimes, a name that sounds suspiciously like Juliet Capulet.
Like the Capulets and Montagues taken to the extreme, these two aren't just on different sides of the tracks—they're on different sides of life. R's a slowly decomposing corpse and Julie, well, she's not. She loves pad thai, sushi, and cheeseburgers (not brains), and is really into music: "Music is life! [...] It's neon ecto-energy sucked out of spirits and switched into sound waves for your ears to swallow" (1.7.34). Okay, she's a little tapped. No wonder falling in love with a zombie is easy for this girl.
To be fair, though, Julie's attraction to R isn't instantaneous. She calls him a corpse early on, and clearly finds him scary. But before you know it, she'll calling him the least-zombie-looking zombie she's seen and telling him his eyes are purdy. Sounds like love to Shmoop.
When R catches Julie soliloquizing it up on her balcony, (sound familiar?) she wants to smooch him then and there. Yes, even though he's dead. She isn't sure if locking lips with a zombie is going to kill her or not, but she tries it anyway. Must be Juliet's suicidal tendencies coming out.
Julie's dark past is hinted at by the scars on her wrists "too symmetrical to be accidents" (1.7.20) and her rationale for doing hardcore drugs: "All the s***ty stuff people do to themselves... it can all be the same thing, you know? Just a way to drown out your own voice. To kill your memories without having to kill yourself" (1.7.60).
Strangely, it's becoming a little dead on the inside—by absorbing whatever R has that made him a zombie—that ends up curing the zombies. So, by being a little dead on the inside, we can, you know, not be dead. Or something? It's unclear. But hey, at least R and Julie don't have to actually kill themselves like their namesakes, right?
The gist here seems to be that the divisions between the Dead and the Living are not so clear-cut. If a Dead guy can love a Living gal, what's the point of calling them Dead and Living in the first place? And the fact that Julie's eyes turn gold, and they both have that sexy new pheromone smell tells us that these two have grown more like each other. Somehow, that connection helps humans accept sensitive zombies into their mix, hinting at the fact that what has divided them for so long no longer exists.
If we had to describe Julie using one word it would be forgiving. She not only forgives Nora for sleeping with her first boyfriend, Perry, she forgives R for eating Perry. Or maybe she just never really liked Perry. Who knows?
If we had to describe Julie using two words, we'd add hopeful to forgiving. Her bedroom looks like the inside of a Rubik's cube with each wall a different color. That blank yellow wall? That's her "hope wall" (2.2.113). Okay, so Julie's not the best interior decorator. (She should call Carly Rae Jepson maybe and get some tips.) But at least the girl has hope, and that's what ends up saving R. Their general hope for mankind, and for life, ends up coming true.