The whole Intoxication Ensues sequence in "The Windbreak War". In the end, just this once, even Margo gets the joke. (Which makes it double as a Crowning Moment of Heartwarming.)
And even more of a CMoH in that the amusing event that sets Margo off at first horrifies the other three (afraid that Margo will blow up), until they see that Margo doesn't mind and begins laughing hysterically. They follow suit and let themselves laugh as well.
When they're trying to get the harvest in ("Backs to the Wall"), Margo comes to help in a bright yellow waterproofs. And then proceeds to pick runner beans. One at a time.