6) The Trouble With Tribbles

Original Trek’s funniest episode is, perhaps by default, Kirk’s funniest episode. He gets to be the put-upon captain surrounded by ever-growing masses of purring fuzzballs, but he also just gets to be the cocky dude that has become in many ways our de facto impression of Kirk. It’s just that this time, he turns that devil-may-care cockiness on a fellow Federation official, in the form of snooty Under-Secretary Nilz Baris (who definitely deserves it).