As others have noted before, according to TV-reality, the US is primarily made of serial killers and sex criminals, which is a stark contrast to real reality, where we are largely made of cheese and color additives.
Hannibal takes this observation to the logical conclusion: if everyone is a serial killer, then even the people trying to stop the serial killers are going to be serial killers. Or at least incredibly unstable people with points-of-view that would make Lovecraft say, "Nah, bro, too dark."
I won't say too much because I (a) don't want to spoil it for anyone and (b) am not done with the first season myself. I will say that it is a show that really highlights how crazy American standards are for violence vs. sex. To wit: there are a lot of dead people, many naked, but we'd never see that much skin on a primetime, major network show if the body was alive and in bed rather than, say, draped over a table of antlers in a field.
It's also a show that beautifully breaks one of the cardinal rules of scriptwriting for many genres: "dialogue should be like real talk, only better"; or "... like real talk, with the boring bits removed." Many beginning screenwriters (::cough:: me ::cough::) and many beginning drafts may start with dialogue that's really helpful to the audience, but not at all realistic.
"Why did I ever listen to you when you told me that this mine held the lost diamond that would buy my family's farm back from that evil developer" is not something someone would really say. "I'm so mad at you for leaving me, especially because of my abandonment issues after my dad's plane crashed under mysterious circumstances" might work in a comedy.
Or put another way: When Han Solo brags that the Millennium Falcon is the ship that made the Kessel run in less than twelve parsecs, we in the audience don't think, "wow, I can barely get dressed and out the door in less than twelve parsecs." We think, "Boy, this guy really loves his ship / is full of shit." The content of the line gives us less information than the tone and context of the line. The beginning writer forgets that and tries to jam info into the words, usually using too many.
In Hannibal, certain characters--mostly the dangerous killer Hannibal and the unstable criminal profiler Will Graham--speak occasionally as if they've wondered in from Clark Ashton Smith or Thomas Ligotti. (Now I can use Thomas Ligotti as an example, thanks to the plagiarism brouhaha over True Detective, so--thanks, True Detective!)
And it's great precisely because it's so weird and precisely because the content of the lines is still less important than the tone and the context. Hannibal may go on about how the enclosure turns the tortoise into a god--oh, wait, that's Twitter's Hannibal at the Zoo--which doesn't really tell us anything about the tortoise, but tells us all about Hannibal's weirdness.