Enforced Method Acting: Lydia Mackay comments that in her role as Shion, she had to place an unlit cigarette between her lips in order to realistically portray Shion speaking with a cigarette in her mouth.
I Knew It: Not too surprisingly, considering the show's excellent use of clever foreshadowing.
Kougami used to be an Inspector.
Also Shogo being immune to the Sibyl System.
Masaoka being Ginoza's dad. Due to the mention of Ginoza's father being a latent criminal combined with Masaoka's age and fatherly air, many fans guessed it episodes before it was revealed.
There were viewers who guessed that Togane was connected or related to the Sibyl System in some way due to the opening hinting so, they were totally right. One of the Sibyl Systems brains is his mothers. He works for her!
Playing Against Type: Lindsay Seidel mentions in a commentary that Yayoi is this because she was told by the production team to use a lower voice than her normal one, which surprised those who follow her work.
Reality Subtext: Each episode of the first season was making an effort to be set almost exactly 100 years ahead of the present day. To wit: the show began airing in October 2012, and the first episode occurred on November 4, 2112 note This can be extrapolated by the second episode's beginning, which happens the day after and Akane's holo-assistant states it's November 5. Akane's alarm clock also states it's November 5, Wednesday, which is a Critical Research Failure because November 5, 2112 is actually a Saturday. Another example would be episodes 10 and 11, which take place on December 24, 2112; these episodes aired on December 14 and 21, 2012 respectively. This pattern began to break with the second half of the show, which featured events taking place in very close proximity to each other (such as episodes 18-22 which occur within a five-day timespan). The fact that there was a two month Time Skip in the last episode, though, may hint the show's timeframe got back on track with the 100-year "real time" gap.
The second season premiere has a moment where Mika mentions she's been an Inspector for a year and a half. Mika became an Inspector in the final scene of the first season which aired at the end of March 2013. The second season began in October 2014, which is just a few days over a year and a half.