The One With Two Parts (2) - Episode 17:

: The "evil twin" dynamic was established here to explain why Lisa Kudrow was appearing on both Friends and Mad About You (where she played Ursula the waitress). Phoebe’s decision to impersonate Ursula to give Joey a "clean break" shows her profound loyalty and empathy, even when it means hurting her own feelings.

: For perhaps the first time, Joey is truly heartbroken. His infatuation with Ursula leaves him blind to her apathy, highlighting a naive romanticism that would reappear throughout the series. Trivia & Lasting Impact Episode 17: The One With Two Parts (2)

: The episode ends with Marcel the monkey choking on Scrabble tiles, requiring a hospital visit that ironically resolves Ross's fatherhood anxieties as he holds the monkey’s "hand". : The "evil twin" dynamic was established here