3. Much of the episode feels relatable
One of the aspects of "The Trouble with Tribbles" was that much of the comedy was wrapped in relatable situations that viewers back then could relate to. Kirk's absolute loathing of Nilz Baris and his endless bureaucracy, his irritation at the way his employees were behaving, and a passive-aggressive leader from another company was constantly fake-complimenting him every five seconds. Those working in any corporation or field that included a low-key toxic "company culture" back then probably found themselves laughing!
The space station bartender (Guy Raymond) and Cyrano Jones (Stanley Adams) might have reminded viewers then of a rapid-fire duo like Abbott and Costello because they stole every scene they were in.
Their interactions had a vaudevillian edge, especially during the Klingon/Enterprise crew brawl and their actions were silent, like Cyrano Jones trying to help himself to a free drink, only to have the bartender breeze by and take it. Jones revealed another stolen drink from the pocket of his jacket, and the guzzle he took was pure, "So there!" (Pinky in the air and all!) It was ridiculously familiar, even today!