These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Family-Unfriendly Aesop: It's perfectly fine to fall in love with the guy stalking and scaring you. He secretly loves you and it will all work out fine. Also, if your female therapist warns you to stay away from the guy treating you very inappropriately, just ignore it. She's just a jealous bitch trying to get in the way of True Love and wants the guy for herself. And if your friend also warns you away, ignore that too because your friend has just been tricked.
Nora is a human albeit descended from a Nephilim and Patch is an angel. They're in a relationship together. If they had a child, said child would also be a Nephilim. In the books, Nephilim are hunted down by fallen angels and forced to take an oath that makes them immortal and lets the angels possess them for two weeks every year. And in Crescendo, we see fallen angels are willing to do that to Nephilim younger than sixteen. By forcing it with a gun.
We also see that between only having two weeks in a year when they can experience physical sensations and a desire to conceive Nephilim to get back at the angels in heaven, fallen angels enjoy possessing their Nephilim vessels to have sex. According to Jules, Nephilim are completely conscious for this.
Idiot Plot: The story would probably have finished a lot sooner if Nora would have just told her mother that she was being harassed and stalked, or reported Patch and her Biology teacher to the school Superintendent (both of whom were violating the School Code Book, promising all students safety on school grounds).
Les Yay: Nora's description of Dabria in Silence is questionable at best.
In Crescendo, Nora ends up in a catfight with Marcie, during which point Marcie straddles Nora while she's on the floor. Following this, Vee licks Nora's arm (she'd spilled Cherry Coke on it) and comments that Nora tastes delicious. Erm...
Rooting for the Empire: In the series, the archangels are written as being extremely unfair, because they threaten to throw Patch into Hell if he pursues a relationship with Nora. The trouble is, Patch is written as an arrogant idiot who spends his days gambling and groping Nora, not showing the slightest inclination to actually do his job. As a result, the archangels come across as trying to get Patch to shoulder some responsibility. Add in the fact that Patch spent almost all of the first book stalking and assaulting Nora and the idea of him facing serious punishment sounds rather nice.
Strangled by the Red String: Patch and Nora, full stop. Nora is warned by people who care about her to stay away from him, because he's clearly not a good person in any way, shape, or form. Patch stalks Nora, intentionally scares her, sexually harasses her, mind rapes her, and possesses her body* Not like that, although no one's putting it past him.. On top of that, his original plan was to murder her in cold blood, which he flat out tells her — and, when she asks if he's going to do it, he admits that it's "tempting". Not in the dubiously-understandable Edward Cullen resisting-physical-temptation way, either. Patch is tempted to murder Nora simply because he feels like it. Nora even says, more than once, that she sees absolutely nothing good about Patch. Wait, why does she fall in love with him again?
Vee gets this when she hooks up with Rixon in Crescendo. The two are hardly shown together and for all Vee fawns over him as the "perfect" boyfriend, there's precious little on them actually having anything in common. Fridge Logic also sets in when Vee repeatedly states that she thinks that Patch is a jerk and a potential murderer but isn't the least bit concerned about the fact that he introduced her to Rixon (and that Rixon is Patch's best and possibly only friend). Not to mention the fact that Vee seems quite certain that he's a "boyscout", despite the fact that he more or less lives in a very nasty bar and is not exactly shy about dropping crude innuendos towards Nora. That could be chalked up to Vee being a Horrible Judge of Character, except that Nora also thinks that Rixon is "cool" and sees no problem with them dating, even though she knows that Rixon is a fallen angel who possesses a Nephilim for two weeks out of every year for sex (with said Nephilim being conscious for it all). The fact that Patch hooked Rixon up with Vee as a response to suspecting that Rixon was murderous just raises even more eyebrows.
It doesn't matter if a guy stalks you, scares you, manipulates events to get you alone with him in an isolated area, and generally forces his will on you. If you put up with it, he'll change his mind and fall in love with you and you'll have a hot boyfriend who will always watch over you and follow you around.
Patch is pretty much the perfect stereotype of an ethnic gangster - swarthy, dark complexion, extremely Italian last name, a love of hanging around in bad areas of town, and seducing/taking advantage of a pretty white girl.
At several points in the novel, Nora is told by the school guidance councilor that Patch is not safe to be around and that she highly recommends that Nora does not hang around Patch off school property or by herself. The advice is perfectly logical, given that Patch is scaring Nora with his behavior, but Nora instantly is suspicious of the advice. And then the end of the book proves Nora's suspicions right, by having the councilor be a Clingy Jealous Girl who wants to drive her away from Patch.
Nora, in the early parts of the book when she clearly doesn't want anything to do with Patch.
The Nephilim in general. They have no control over their parentage and half of the time they have no idea they're Nephilim at all. But if a fallen angel finds them, they're forced via Mind Rape to put themselves for an eternity into said fallen angel's service. They then get their bodies stolen for two weeks out of every year, during which time they're forced into an And I Must Scream situation while the fallen angel uses them for various things, including sex.