Holy shit, do you have five months?
Okay, basically here’s the thing: Will and Hannibal have a very destructive relationship based on mutual need. Will needs Hannibal to lean on, to make him feel safe, because Hannibal doesn’t judge him for his condition, nor does he try to use him for what he can do. So in Will’s eyes (even though he’s WRONG) Hannibal is the only person that he interacts with who only cares about him.
Hannibal, on the other hand, needs Will because Will understands him. Even though Will doesn’t realize it, because he doesn’t know who Hannibal is, but you can definitely see how important it is to Hannibal whenever Will talks about the Chesapeake Ripper. I think he almost likes it better knowing that Will can understand him without even knowing that it’s him. I think he gets off on knowing that there is at least one person out there that follows his train of thought, particularly since he’s the kind of serial killer that displays his victims. He wants people to know him and appreciate his art, and Will does. Add that to the fact that Will is basically completely broken emotionally, and it’s really easy for Hannibal to manipulate him into doing exactly what he wants. Which, I think, is why Hannibal deliberately withholds medical information from Will. It has nothing to do with studying him and everything to do with maintaining emotional control over him.
So I basically just explained why it’s a terrible, dysfunctional, fucked up relationship, which is really kind of why I like it? Which makes no sense, I realize, but it’s true. They are both fundamentally broken individuals in very, very different ways, and their relationship is massively unhealthy, but they genuinely care about each other (in Lecter’s case, it’s not really caring the way normal people care but, you know, he’s an actual psychopath) and there is something really, really compelling about that to me.
In short, I LIKE DAMAGED PEOPLE FINDING A TERRIBLE FORM OF LOVE WITH EACH OTHER!