It's in the official Gene Roddenberry biography. And the book written by Herb Solow and Robert Justman. I don't have them in front of me at the moment so I can't quote the exact lines and pages. But Gene, Herb and Rob all talk at various points about the problems between Nimoy and Shatner.
Someone told me not to believe everything Gene Roddenberry said, so I will take this with a grain of salt.
I don't know exactly what happened between him and Mr. Shatner, but certainly Mr. Shatner said he did not try to get close to Roddenberry, while Mr. Nimoy and Mr. Roddenberry mutually disdained each other. Since Mr. Roddenberry also had a reputation of being very creative about generating publicity for Star Trek as well as making profits from Star Trek, I suspect he might not be the best person to examine the relationship between Mr. Shatner and Mr. Nimoy.
And then there was the amount of attention that Nimoy got on set for makeup and lighting. Shatner felt that they were fawning over Nimoy and leaving him out. As well, Nimoy, because of his extra makeup requirements had to be on set earlier and leave later than everyone else. The third season episode "The Enterprise Incident" came about partly to slightly remedy this. By having Shatner wear Vulcan ears (or in this case Romulan ears) he could see what Nimoy had to go through, though just briefly. And try something different, and get the attention he felt he was missing out on, on set.
Mr. Shatner said he only needed 15 minutes for makeup. He joked Mr. Nimoy needed 3 hours because he was "uglier" than the rest of the cast. LOL I don't know if he actually was missing all the attention Mr. Nimoy was getting for makeups. He does not seem like a person who can sit still for 5 minutes anyway.
Nimoy: When I directed Star Trek IV, I got a good performance out of Bill because I respected him so much.
Shatner: And when I directed Star Trek V, I got a good performance out of me because I respected me so much.
LOL. This is hilarious.
Didn't he make fun of himself in SNL by showing off his physique in front of a mirror? And I always wondered where "I am sorry, I can't hear you over the sound of how awesome I am" came from.
"I wasn't so much acting as I was reacting, using my own internal makeup as the spine upon which I was able to build the character of Jim Kirk. We were bascially one and the same, although Jim was just about perfect, and of course, I am perfect!" LOL
Yes, it's about people's perception of him too. As a result, he has always been interesting to the public. That reporter was correct, a Shatner without controversies would have been boring.