TOS Spock's, who in the series was much more repressed and therefore tended to have outbursts of happiness or rage when circumstances got intense.

I remembere one episode where for some reason Spock had to fight Kirk to the death, and Bones arranged for it to look like Kirk was dead when he wasn't, and later when Spock found out he broke into a HUGE grin and shouted "JIM!" And when everyone stared at him like he had two heads, and quickly went back to normal and said something very Vulcanish. :D