TBH, I was kind of getting tired of the Spock/McCoy racist banter with one another after 3 seasons of if. I'm glad the movies gave them some character development wherein they both got over it (more or less) and grew as characters.
It was still there in The Wrath of Khan and in bits and pieces in the other films.
Well, after TMP Spock finally realized his "Logic is better" stuff was all BS and it ultimately led to an empty existence, so he finally realized he'd be better off just accepting his irrational human side. He had a far more content life after that.
After the TWOK/TSFS thing wherein McCoy had Spock in his head, he toned down the racism.