Zodiac
This and Memories of Murder. Two sides of the same coin. The paranoia and the obsession. It doesn't come from the fact that the detectives and cops couldn't catch the killer, it comes from the fact that the killer left so many clues, the killings have a pattern, and we as human beings, crave patterns and connections. Having so many, each dot connecting with other and then at the end, even after feeling like you know a lot, the result makes you feel like you don't know anything. Also, 50th movie of the year for me (apart from the re watches)