Star Trek IV: The Voyage Home, may be the third-best film of the original trilogy. It's often considered one of the better stories Star Trek ever did that didn't have anything to do with some type of war or villain trying to get revenge. It's mostly just a story about the crew of the Enterprise using an old Klingon ship to go back in time and save the whales.
It's really that simple. It has a legion of fans who support this film and it's helped create many legendary scenes that still live on in the Trek zeitgeist all these years later. But that doesn't mean that it was a film that didn't have some problems behind the scenes.
Catherine Hicks was new to the cast for the project and played Dr. Gillian Taylor, a cetologist who helps the crew of the Enterprise save the whales. But while Taylor was there to help the crew of the Enterprise, it was the crew of the Enterprise who helped Hicks. Namely, Leonard Nimoy, who not only reprised his role of Spock for the film but also directed the film as well.
According to a StarTrek.com interview (via SlashFilm) with Hicks, she apparently had issues with William Shatner and his desire to hog the spotlight, butting into her scenes as often as he could; according to Hicks. This caused her to go to Nimoy directly when he wouldn't relent, with Hicks saying;g
"I remember the fun, the kindness, just the kidding around, the joyfulness, and fighting for some close-ups, the tug of war with Bill (Shatner) for close-ups. It taught me to stand up for myself. I'd go to Leonard and say, 'This is MY shot. I need a single. I'm not going to share the shot with Shatner.' He wanted to get in every shot, but you couldn't get mad at him because he was like a devilish brother."
Shatner's on-screen behavior isn't new to many fans, as his antics are a major reason why George Takei can't stand him, and vice versa.