Admiral Buzzkill wrote:
The fact that Sturgeon showed the Vulcans to be virtually the opposite of what we expected is one of the most wonderful things about the episode.
As someone smart once said, "You want to find out what people are doing a lot of? Look at what they make laws against."
The episode actually addresses this, when Spock asks Kirk if he ever wondered how Vulcans pick their mates. Kirk shrugs and says something about how he always assumed it was done very logically.
"It is not," Spock corrects him--which was indeed nicely unexpected.
(This is the part where I reminisce once again about appearing on my very first convention panel opposite Theodore Sturgeon of all people. I was more than a little intimidated, especially considering that I was just a baby writer with only a few magazine credits to my name, but he couldn't have been nicer or more hospitable.)