* Quite a few - Duane is the sort of writer who can sneak up on you and leave you gasping for breath. The acme of all these moments, though, has to be when [[spoiler:Kirk finally gets fed up with [=McCoy=]'s kvetching and puts him in command of the ''Enterprise'']] in ''Doctor's Orders''.
* ''Dark Mirror'': The whacked-out improv opera at the end.
** Related to this, Worf's line about a particular Klingon opera: "There was fighting in the streets for three days, and the government fell. And ''then''-" *interruption ensues*
* From ''Spock's World'' - [=McCoy=] vs. several Vulcans. The good doctor has surprising compassion (especially considering [[Recap/StarTrekS2E1AmokTime what happened the last time he was there]]), but he won't take any illogical anti-human guff off anyone and gets in some good jabs that are part insult and part calling out.
* In one of her ''Franchise/StarTrek'' novels someone mentioned the roller coaster. Chekov, for once telling the truth, stated it was originally invented in Russia... [[CassandraTruth And nobody believed him]].
* Every time a Romulan encounters an Narhat, for the first time. Why? Romulan religion worship elements... And Narhat, being an [[StarfishAlien Horta]], just looks like living Earth, pulling an accidental GodGuise.
** Narhat does it on purpose in ''The Romulan Way'' on ''the whole Romulan Empire'': they were broadcasting [=McCoy=] [[KangarooCourt alleged trial]] before the Senate when Narhat broke in.
** In ''My Enemy, My Ally'', Ael and the crew of the ''Enterprise'' are on a Rihan space station, and need to pass through a door that is too dense to penetrate with their weapons. Ael's solution? She had Narhat ''eat it''.