During Rosa's last phone call, the actor playing her abruptly changes from the one who plays Susan to the one who plays Michael (because the actor who plays Susan just finished singing a huge number and needs to rest her voice). The phone call starts earnestly enough, but as it continues with Rosa crushing Jon's dreams of Broadway, it morphs into what is clearly Jon's impression of that phone call rather than anything she would actually say.
Rosa: Honey, we always knew it's a little quirky for Broadway, and the cast is awfully big for Off-, and the futuristic thing means sets are expensive, and musical theatre is Newark Airport and you're snowed in at Buffalo––and now, having plucked out your heart and eaten it like a piece of ripe fruit, I'll leave you to sweep up the fragments of your shattered dreams, bye-bye honey! Happy birthday!
The market research meeting where they try to come up with the name for this fat-free oil. The whole thing gets increasingly absurd, and no one but Jon and the audience seems to realize it. Eventually, Jon shuts down the entire conversation by offering his name for the product: "Chubstitute."
Jon: Rather than call security, Judy allows me to leave the building under my own power.
In a scene that was clearly drawn from the director and screenwriter's own experiences, Jonathan spends a good 30 seconds deciding on writing "your" or "you're."
The market research scene is even funnier due to the hammed up performances of Laura Benanti, Micaela Diamond, Utkarsh Ambudkar, and Danielle Ferland. Jonathan's relaxed "This could be the rest of my life," and later horrified "This could be the rest of my life!" also marks a welcome addition.
"Sunday" is funny as always, but there's a joy in recognizing all the Broadway cameos that have been shoved into this one song.
How does Jonathan try to ignore the phone as he's composing a song? He shushes it.
Also, that song sounds suspiciously like "One Song Glory" from his later musical RENT.
Rosa's summation of Jonathan being nervous about his workshop.
Rosa: Of course you’re nervous. The first presentation of your musical is like having a colonoscopy in the middle of Times Square. Only, with a colonoscopy, the worst thing that could happen is, you find out you have cancer. With a musical, you find out you’re already dead.
