After the first rough ride through the radiation belt, when Kirk announces the ship will stand down for repairs, Uhura says: "After that ride, I could use some repairs."
The computer has fun ordering Kirk around when he wants to know what happened to McCoy, Uhura, and Sulu.
Computer: Say "please." Spock: Compliance would seem to be the logical response, Captain. Kirk:[gritting his teeth]PLEASE. Computer: Say "pretty please with sugar on."
Spock: Captain. I am only a Vulcan. There are limits.
"More Tribbles, More Troubles" is a Call-Back to TOS's most hilarious episode, "The Trouble with Tribbles", and introduces a number of new gags:
Remember when Kirk accidentally sat on a tribble that was in the captain's chair? This time, there is a Running Gag where a large tribble chooses the same spot. Twice, Kirk has to shove it off. The third time, it's too large to deal with, and he concedes: "I think I'll stand."
The glommer, a critter that eats tribbles, meets a gigantic one and flees in terror.
Cyrano Jones insists that he has a right to the glommer under space salvage laws. Scotty points out that space salvage laws only apply in space, not planetary surfaces, but "kindly" offers to beam Jones over to the Klingon ship in order to recover the glommer himself. Jones immediately withdraws his claim.
Finally, at the end McCoy has begun to administer a treatment to the tribbles which keeps them from endlessly reproducing or forming giant colony balls. Kirk notices one that's up a Jeffries tube and calls attention to it, but he has barely finished speaking when the ball disintegrates into individual tribbles and buries the captain once again.
Kirk: Someday I'll learn.
The Enterprise crew's Oh, No... Not Again! reactions when they realize who they've rescued, and more importantly, what he has brought aboard with him. Kirk looks like he's considering the possibility of just letting the Klingons have the "general trader and interstellar nuisance."
When Koloth demands that Kirk hand Cyrano Jones over to him, Kirk notes that it pains him to admit that Jones is a Federation citizen in Federation territory and thus Kirk must refuse, despite any unspoken temptation of his to just let him be Koloth's problem.
Everyone's WTF reactions when, in "Time Trap", Spock starts acting chummy with the Klingons, with handshakes and stuff. The Enterprise team can only sheepishly apologize, and the Klingon team leans towards the conclusion that the time trap barrier/stress has messed with his hybrid mental makeup (which would be seriously bad news, as it is his calculations that their escape plan hinges on). Of course, this was part of the setup: Spock was using touch telepathy to divine the Klingon's plan, beyond escaping.
"Once Upon a Planet":
While on the planet where thoughts come true, someone thinks it's like "cat and mouse", a giant cat attacks them.
From the same episode, McCoy's Alice in Wonderland thought comes true again but it's the Queen of Hearts and her playing cards. McCoy describes them as "a group of playing cards, only they weren't playin'".
The sentient computer thinks people are the slaves of their "sky machines" and states that it will "turn off" Kirk, Spock, Sulu, Scotty and McCoy. When Uhura says, "You mean murder them?", the computer asks if murdering will make them cease to function. Uhura says yes, to which the computer basically says, "That's what I want. I'll turn them off."
At the end, Sulu and McCoy are seen having a picnic with the dragon robot.
McCoy says, "Are you expecting signs pointing the way?!" as a rhetorical question, but then:
Spock: Captain, signs pointing the way.
Spock is not beating the "would fall in love with a computer" allegations.
In "The Counter-Clock Incident", which largely takes place in an Alternate Universe where time goes backwards, the crew start de-aging. Kirk and Sulu become teens and Uhura becomes an eight-year-old. Kirk has forgotten the meanings of some sci-fi words and Uhura is crying.
Spock makes contact with a nebula-ish creature that ate them in hopes that it will, for lack of a better phrase, spit them out. It's funny because, well, imagine hearing someone say that to you.
Spock: We're inside you. You thought we were food.
In "The Ambergris Incident", Kirk and Spock are made into water-breathers and McCoy tells them he doesn't know how to turn them back.
Kirk: I can't give orders from an aquarium in Sickbay.
In "The Terratin Incident", everyone shrinks. It's comical seeing a shrunken crew trying to run the ship. Then, when Kirk grows back to normal and holds the small communicator.
"Mudd's Passion":
M'Ress starts flirting with Scotty and calls him "attractive for a human".
Hearing Spock describing Nurse Chapel in poetic terms.
It also makes Kirk and Spock act chummy towards each other and the after-effects are everyone being grumpy. Spock even calls an idea "stupid", then instantly apologizes.
When a shapeshifter knocks McCoy unconscious in "The Survivor", he states that he must have taken a nap. Spock says that while McCoy is a bit eccentric, it's not like him to nap on the floor of the science lab.
McCoy:[about to give an injection] This won't hurt a bit, Spock. Spock: An unnecessary assurance, doctor, in addition to being untrue. McCoy: That's the last time I waste my bedside manner on a Vulcan.
Kirk, Spock, McCoy, and a Redshirt are taken captive by a planet of women who operate their technology by singing to it. When Spock escapes, he sings in the same high-pitched siren song to operate things.
The siren's song sent out by the planet renders the men into helpless fools, including Mr. Scott, currently in command of the Enterprise. Uhura matter-of-fact informs Scotty that she is taking command, and he cheerfully agrees that it sounds like a wonderful idea, obviously too subdued by the song to care one jot either way.
Something about the sight of a landing party consisting entirely of scowling Redskirts blasting away with phasers on stun. Possibly the most violent scene in the entire show and hilarious for the Mood Whiplash of any Starfleet landing party rolling in so heavy on an otherwise fairly lighthearted show.
"Yesteryear" is a fairly serious story, especially as it mostly takes place on Vulcan. However, there are some funny moments.
There is something hilarious about the idea that young Spock had a reputation among other Vulcans as a practical joker, because he played a prankonce.
The fact that the beast Spock nearly gets killed by uses Godzilla's roar.
And this little gem:
Young Spock: Will I ever learn to do that neck pinch as well as you?
Old Spock: I dare say you will...
Also, Young Spock telling I-Chaya to go home because I-Chaya is old and fatnote difficult not to imagine him saying that to movies-era Kirk, the sass in Young Spock's line read on "I did that once... TWO YEARS AGO!", and the way he matter-of-factly excuses himself to go neck-pinch his bullies... um, schoolmates.
◊" moment.
