Serial Experiments Lain
This is just another anime that screws with your mind. I will probably never be able to get my mind back to a pre-Lain State. Just like what Chaos; Head did to me it shattered my thought process several times to only have me rebuild and do it again. Nothing was as it seemed and I had to look at below the surface to truly appreciate what was being said. This definitely had sci-fi written all over it. It showed what could go wrong in a world with too much technology.