Complete Monster: Charles Zurich, from season 4's "Sky Knight", ex-agent and leader of the New Dawn movement, is a Faux Affably Evil extremist vying for the release of 197 "political prisoners" under the threat of murdering a plane full of innocent people. Zurich's seemingly good intentions are a farce, as he secretly intends to use these prisoners—all of them merely cutthroat murderers-as his own private army to wage wars upon and take over any small country he wants. Gleefully attempting to execute Michael Knight's love interest with the intent to hurt him, Zurich finally just tries to wipe out all the hostages with a nuclear doomsday device, even leaving his own men to die the second they hesitate.
The success of the Transformers movie was a major influence on KR08's pilot movie, and the subsequent show borrowed a lot of design elements (including the transformation style), culminating in bringing Peter Cullen back as the voice of KARR.
Ironically, the transformation style had previously been attempted in Viper, which was a distant Follow the Leader of the original Knight Rider.
Fridge Brilliance: The show has had three examples of Evil Twin, one of which was KARR, KITT's evil twin. At first, this seems like a further effort to establish the car as a character. But when you think about it, KITT is more likely to have an evil twin than the two humans (Michael and Devon). True, the in-universe explanation is the most likely (KITT is an advanced piece of technology and KARR was his prototype), but creating a copy of KITT only requires getting a third generation Trans-Am and customizing it to look like KITT (which some real life fans have no doubt done).
The original is considered hilarious in Brazil, thanks in part to an extremely hammy dub. The Mexican Spanish dub averts this through, since the series is still popular in Mexico.
The series was also wildly popular in Spain, where it was renamed The Fantastic Car and achieved an iconic status as a part of The '80s. When the 2008 revival premiered in Spain, it got historical ratings and received two TV runs back to back.
The Japanese-dubbed version is as hammy as the Brazilian dub (you can watch a clip of that dub in the movie Mr. Baseball).
And naturally, the show was an early hit of fledging commercial television in Germany.
Most Wonderful Sound: The "whoo-whoo" of KITT's sensor bar. It doesn't play all the time, but you know you love hearing it every time it does.
Narm: In the episode with KARR, the "No! NO!" that KARR gave when Michael overrode KITT to play chicken with KARR, knowing the latter would veer out of the way due to self-preservative programming, sending it off a cliff and to a rather explosive demise.
Replacement Scrappy: April. Patricia McPherson was fired after Season 1 due to disagreements with Robert Foster, the series' producer. However, after Season 2, Rebecca Holden ended up getting the boot due to fan reaction, and lobbying from David Hasselhoff and Edward Mulhare.