If you find yourself anylyzing the truths and concepts of humanity, and take interest in the thoughts and actions and logic to serial killers' methods, does it make you insane? That's the only word I could use to describe it, but I'd love to hear other opinions.

No, it just means you're interested in behavioral psychology. There's nothing "dark" or "crazy" about it, and any person who would learn of a serial killer and not question his logic would be a rather blunt, unfeeling individual.

"Crazy" only comes in when you decide to use what you've learned.

I do that all the time. It's interesting, but I consider that just normal over-analytic nerd stuff. I do the same thing. Am I crazy? Probably, but that's not why I would peg myself as such. Heck, perhaps we try to think of ourselves ac crazy so we do not have to take personal responsibility for some sort of personal shortcoming(s). I know I've caught my mind self-deceiving into thinking things were just because I'm crazy, or just because so and so is a bad person.

This belongs in Personal.
/sage