Ever notice how Harry just sort of spontaneously has the hots for Ginny Weasley all of a sudden? It comes on pretty quick during the Half-Blood Prince. I mean, you can explain most teenage actions by pointing to their throbbing biological urges, but you figure there would have been some sort of lead-up. By the time Ginny and Harry start gettin' hot n' heavy, Harry was well into puberty and had already cultivated a forest of lightning-shaped pubes.
Yeah, it was pretty obvious that Ginny had a thing for Harry, but the feelings weren't reciprocated for the longest time. Then all of a sudden Harry fell for her and they get married and have kids.
It's like magic. Well, more like a potion. One of the most fucked up things J.K. Rowling ever included in the Potter universe was the love potion, which is exactly what it sounds like: they have the ability to make a target lust after the desired subject. Given the sudden love-in, there's a good possibility that Ginny used that potion to make Harry fall for her, without Harry's consent. Even Ginny's mom admitted to using a love potion when she was in school. Combined with the fact that Fred and George Weasley sell these abhorrent potions, the abuse of the concoctions would seem to run in the family.
Using magic roofies are a violation of trust, not to mention incredibly dangerous. And yet, it explains so much. After years of pining for Harry, Ginny gave into her darker side and secretly spiked his butterbeer with a love potion. It was probably just a few drops; enough to keep him jealous and anxious, but not enough to raise suspicion. All she had to do was keep him dosed at all times and voila! Ginny snagged herself the Boyfriend Who Lived. Look at the way she clutches her property.
Who knows, maybe Ginny is still juicing Harry's chocolate frogs to this day, afraid of the moment that he snaps out of his trance and realizes he doesn't love her. You'd almost feel sorry for her if she wasn't brainwashing another human being.
It's always been kind of weird that the wizarding world has felt the need to hide themselves from Muggles. There's a real air of superiority over the non-magically inclined, if not outright racist then it's sort of a soft condescension; Arthur Weasley in particular treats Muggles as though they were a particularly fascinating meerkat family on NatGeo. So why do the magic-inclined bother hiding at all?
Well, maybe wizards didn't always cower in secret. Maybe they were free and open in the Muggle world, and it didn't end well for wizards.
Anyone familiar with Harry Potter knows that the Ministry of Magic regulates pretty much everything remotely fantastical. You can't say as much as "Accio Corn Dog!" without the Ministry jumping up your ass. It so backwards and beaurocratic that it seems like a Muggle invention. And it probably is.
Really, something like the "Ministry of Magic" sounds like one department in a larger government body, one that might include "Ministry of Agriculture," "Minister of Foreign Affairs" and "Ministry of Mister Mister." So just maybe it's the other way around -- Muggle governments know about wizards and use the Ministry to control them. There might've been a past conflict between Muggles and the Magic, but the sheer numbers (and the advent of gunpowder) made sure the wizards were outdone.
So why don't we see any lingering evidence of this past war? Well, maybe we have, and we never realized it.
Avada Kedavra. The killing spell. A term made up specifically for the Harry Potter, it's always had kind of a familiar ring to it. It seems to have a lot in common with the generic illusionist term "Abra Kadabra." You know, the phrase used by cheesy birthday magicians and terribly catchy 80s songs.
But maybe that means something. Maybe Muggles heard "Avada Kedavra" so much during their war with the wizards that it stuck with them. But over the years, after it wasn't heard as much and magic grew into something as a joke, it got warped into "Abra Kadabra."
I wanna reach out and grab ya
DAMMIT NOW IT'S STUCK IN MY HEAD