The most telling scene is after the mind meld on Delta Vega. Kirk had tears down his face, and is trying hard to pull himself together. Spock Prime apologizes, saying "emotional transferrence is an effect of the mind meld."
Spock is crying his eyes out over the deaths of the Romulans and the Vulcans, but he's not showing it (although his voice did get thick and teary when he said "Jim, I just lost my planet. I am emotionally compromised.")
Makes you wonder what was going on inside during some TOS episodes...
Agree. I thought the same thing