These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Fridge Brilliance: Although the Standards and Practices applicable to 1970's children's programming would never have permitted outright saying so, the nature of the the weapon found in the stasis box in "The Slaver Weapon", along with a picture of an unknown alien, suggest that the weapon was that of an assassin, and the picture that of the assassin's target. Sulu does suggest that the weapon could have been used by a spy, who would have need for an easily-concealable, versatile, and self-destructing weapon—an assassin or hitman would have similar needs as well.
Narm: Sometimes the limited number of voice actors could make things a little silly, as in "The Lorelei Signal," when Nichelle Nichols and Majel Barrett had to voice, like, seven different people.