Star Trek director left the show because of William Shatner and Leonard Nimoy

The stories about feuds between William Shatner and Leonard Nimoy on and off the set of Star Trek: The Original Series have been going on for years. Both actors were charismatic and strong-willed, and while that didn't stop them from being friends off screen, it did affect the set of the series and how those working around them felt.

Captains' Logs The Unauthorized Complete Trek Voyages by Edward Gross and Mark A. Altman included the director of the second season episode "The Trouble with Tribbles," Joseph Pevney's comments on whether or not there was a rivalry between the two actors. He thought if there were rumors about it, they were "probably true." Pevney went on to describe how things could go awry on a set when one character "became a straight man for the other." With both Shatner and Nimoy wanting to be the heroes in the stories, it created some conflict. So much so that Pevney, who had directed some of the series' best episodes, including "Amok Time" and "Journey to Babel", left the series because he "couldn't enjoy working with those two anymore."

Not only had the quality of the writing deteriorated in his opinion, but Pevney thought the writers were scared that "whatever they submitted would be torn to shreds by Bill and Leonard." And with the confidence missing from the writers' room, it made things more difficult, which Pevney pointed out by pointing the finger at the two lead actors.

"They want to constantly be the heroes, and this is the mark of a spoiled actor. This is a guy who reads his mail and is no longer aware of the need for teamwork."

- Joseph Pevney

The change in the atmosphere on the show, the lack of teamwork, and the lack of quality scripts led Pevney to leave Star Trek after having directed fourteen episodes, the last of which was "The Immunity Syndrome."