For an episode that was never a favorite of mine, I've come to appreciate the comfortable-ness of it all. There's a coziness to it that's lacking in many of the other episodes.
Compare the warm interplay in "The Man Trap" between Spock and Uhura, Sulu and Rand, Kirk and McCoy, with the cold & sterile interactions in many of the third season shows.
It's always struck me as odd that Roddenberry could've had such a hand in producing "The Man Trap," where the characters are mostly three-dimensional and the dialogue is often inspired and the Enterprise is so homey -- then done an about-face and ordered the show more "military" and humorless by the time "Spock's Brain" rolled around. (Yeah, there's humor in that episode but it's largely unintentional.)