Spock in the original series goes into his mating season, which is a time where Vulcan emotions become too uncontrollable to repress. Vulcans are ashamed of this loss of control and try to hide it away.

Spock had to fight Kirk because Spock’s arranged marriage wife-to-be was allowed to chose anyone as her champion against Spock when she decided she didn’t want to him. Spock was out of control in full ragemode and only regained his senses when he thought he’d killed Kirk.

Vulcan society has, to my eye, always been one that acts like it has everything figured out but its repression has created just as many bizarre rituals as any other culture.