Bert moans a lot at the end of skits, mainly because Ernie screws him over.
But he cries also in this other skit:
1969 - He bets Ernie that Ernie can't clean up the apartment in 10 seconds before lunch. If he can't, then he gets to eat Ernie's cookie and ice cream dessert.
Of course, Ernie wins and Bert is left crying: "It's not fair...It's not fair!"
I dunno, maybe he's crying. Maybe Frank Oz was on drugs then.
But he cries also in this other skit:
1969 - He bets Ernie that Ernie can't clean up the apartment in 10 seconds before lunch. If he can't, then he gets to eat Ernie's cookie and ice cream dessert.
Of course, Ernie wins and Bert is left crying: "It's not fair...It's not fair!"
I dunno, maybe he's crying. Maybe Frank Oz was on drugs then.

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That's pretty much exactly how I recall this vase skit too. And a couple extra details you mentioned came back to me (like Ernie picturing Bert throwing him a big party). Also neat that you confirmed that it was this skit where at the end Bert says to the viewers, "He's gone bananas, right?". I had posted about wondering which skit Bert said this line and then said I think it might be this vase one.