Dirk Gently (TV series)/YMMV

The books

 * Genius Bonus: If you have a solid knowledge of history, literature, music, hypothetical physics, and computer programming then you're in for a treat.
 * Dirk's ramble about St Cedd "one of the duller Northumbrian saints. His brother Chad was even duller. Has a cathedral in Birmingham, if that gives you any idea." St Cedd's College is fictional, but its namesake was real, and was indeed the brother of Chad of Mercia, whom St Chad's Cathedral is named after.
 * Lostalgia: The Salmon of Doubt anthology features the beginning of a third book that was never written. And its style is so instantly familiar that it feels just like the other books. Then it stops. Just after Dirk has flown to America and encountered a truck carrying a rhinoceros to an unknown destination.
 * Recycled Script: Douglas Adams, who liked to recycle plot elements, based the first Dirk Gently book on two of his Doctor Who scripts: "Shada" and "City of Death". Knowing this helps explain one of the stranger assumptions in the first book: just why Professor Chronotis happens to be a centuries-old man who lives in a time machine. (It's because he's a retired Time Lord.)

The TV series

 * Affectionate Parody: Of Sherlock, at times, such as Dirk describing a case as "boring" only for it to turn out to be relevant to the conclusion of the case he's working on.
 * Uncanny Valley: In-universe example. In the TV adaptation, Dirk has this reaction to Professor Jericho's robot.