Amanda: And you, Sarek, would you also say thank you to your son?
Sarek: I don't understand.
Amanda: Well, for saving your life.
Sarek: Spock acted in the only logical manner open to him. One does not thank logic, Amanda.
Amanda: Logic, logic - I'm sick to death of logic! Do you want to know how I feel about your logic?
Spock: Emotional, isn't she?
Sarek: She has always been that way.
Spock: Indeed? Why did you marry her?
Sarek: At the time, it seemed the logical thing to do.
[In sickbay]
Spock: Doctor, I think I'll return to my station now.
Dr. McCoy: You ARE at your station, Mr. Spock!
Capt. Kirk: Dr. McCoy, I believe you're enjoying all this.
Spock: Indeed, Captain. I've never seen him look so happy.
Dr. McCoy: [To Spock] Shut up!
[Kirk opens his mouth to comment, but McCoy interrupts.]
Dr. McCoy: Shh! Shh!
[Dejected, Kirk lies back.]
Dr. McCoy: [Grinning] Well, what do you know? I finally got the last word.
The Trouble With Tribbles - S2-E15
Capt. Kirk: I want to know what killed these tribbles.
Dr. McCoy: I haven't figured out what keeps them alive yet.
The Trouble With Tribbles - S2-E15
Dr. McCoy: It is a human characteristic to love little animals, especially if they're attractive in some way.
Spock: Doctor, I am well aware of human characteristics. I am frequently inundated by them, but I've trained myself to put up with practically anything.
Dr. McCoy: Spock, I do not know too much about these little Tribbles yet, but there is one thing that I have discovered.
Spock: What is that, Doctor?
Dr. McCoy: I like them... Better than I like you.
Dr. McCoy: I'm a doctor, not an engineer.
Dr. McCoy: Spock, I've always suspected that you were a little more human than you let on. Mrs. Sarek, I know about the rigorous training of the Vulcan youth, but tell me, did he ever run and play like the human children, even in secret?
Amanda: Well, he, uh...he did have a pet Sehlat he was very fond of.
Dr. McCoy: Sehlat?
Amanda: It's sort of a...a fat Teddy bear.
Dr. McCoy: [Amused] A Teddy bear? [Sarek comes and takes Amanda away.] A Teddy bear [to Kirk].
Spock: Not precisely, Doctor. On Vulcan, the Teddy bears are alive...and have six inch fangs.
The Trouble With Tribbles - S2-E15
Trader: Four credits.
Cyrano Jones: Is that an offer or a joke?
Trader: That's my offer.
Cyrano Jones: That's a joke.
A Piece of the Action - S2-E17
Spock:Young man, this is likely to be quite hazardous. If I were you...
Kirk: Hold on, Spock. Out of the mouths of babes...
Kid: Who ya callin' a babe?
Kirk: I'm callin' you a babe.
Kid: You callin' me a babe?
Kirk: Yeah, I'm callin'... [Kid brandishes a knife, Kirk continues.] I'm callin' you a babe, but there's nothing personal. Sit down.
Answer: Kirk was getting his physical and Dr. McCoy probably turned off communications, because if he hadn't, Kirk would have left and headed straight for the bridge, leaving McCoy irritated.