Kirk: "Spock, you didn't fill out the log?"
Spock: "As it is in fact the Captain's log, sir, I am afraid did not." *eyebrow raise* "Unless I have recently received a promotion I was not aware of?"
Kirk: "... There are times I wonder."
Kirk: "Nothing, Mister Spock." *smiles wryly* "Rebuke duly noted."
Spock: *innocently* "And logged, Captain?"
Kirk: *glances across sharply* "... Just who is running this vessel, Mister Spock?"
Spock: *still innocent* That would be the Captain, sir.
Kirk: "Uh-huh." *pauses thoughtfully* "And the Captain would be the person who fills out the Captain's log?"
Spock: *nods seriously* "Indeed."
Kirk: "I see." *smiles faintly* "So what you're really saying, Mister Spock, is that you couldn't fill out the log, because that would have been disloyal and created a confused picture of authority on this vessel, and you wouldn't do that to me. That about right?"
Spock: *raises eyebrow, then deadpan* "Absolutely, sir."
Kirk: *smiles* "Thank you, Mister Spock. That means a lot." *thinks for a moment* "So. What needs to happen here is that only the person who is definitely and unassailably in charge of the ship should fill out the log." *pauses, grins* "Well, there's only one solution, then!"
Spock: "Indeed, sir." *smiles faintly* "Shall I tell Doctor McCoy that he may begin filling out the Captain's log as soon as is convenient?"
Kirk: *grins broadly* "Spock, you are truly a man after my own heart."
Spock: "Indeed. And in the morning, the doctor will be a man after both our hearts."
Kirk: "The perils of command, Mister Spock. The perils of command."