I need to go with Turnabout Intruder upon some further reflection. It's the series finale (even though such a concept wasn't really the same back in 69) and it really has very little "Star Trek" elements in it. But, the worst part is that in the FINAL episode...Kirk isn't even Kirk. Our hero and the star of the series has his body stolen by a lunatic ex-girlfriend.
It
is God awful, isn't it? (Sorry to any TI fans out there!) What a terrible way to end the series IMO. Would have been better to have ended with 78 episodes and not even have bothered with this script. I mean Kirk/Janice ordering the
execution of the senior officers including my man Scotty? Hell to the no.