In the Methuselah thread, Metryq mentioned that Spock was crossing a dangerous line by making Kirk forget Rayna. Come to think of it, Kirk's mind gets interfered with a lot in TOS.
In "The Enemy Within," he is literally of two minds-- on every subject. How does he bounce back from that?
"Turnabout Intruder" sends Kirk's mind where no man has gone before, but the whole thing is portrayed as not really messing with his consciousness. It just gets transplanted intact (which defies modern neurological theory, but what are you gonna do?).
My favorite "Kirk's Mind" event is when Helen Noel has Kirk in the mental treatment chair and she's re-writing the Christmas party. That was sexy. The fan-fic or R-rated version of that would be even better. What if Dr Adams was busy torturing somebody else (doctors keep us waiting all the time) and Helen had more time? Maybe she would have gone rogue and taken the session in the same direction as Adams himself did, for her own benefit. Hmm.
Other cases of messing with Kirk's mind merit discussion as well.