The sitcom staple Monica had a crush on Joey when he first moved in across the hall, and prior to Phoebe (Lisa Kudrow) marrying Mike (Paul Rudd) in season 10, Friends teased Phoebe and Joey getting together on multiple occasions.
While Joey getting together with Monica and Phoebe could have drastically altered the show, it was the later relationship between Joey and Rachel (Jennifer Aniston) that caused quite a bit of controversy. In Friends season 8, Joey graciously offers Rachel a room in his apartment while she is pregnant with Ross' (David Schwimmer) child. Over time, their connection grows and the soap opera actor comes around to the idea that he may have feelings for Rachel. Joey even tells Ross (David Schwimmer) how he feels, and Ross ultimately says he won't stand in the way of the two being together.
The Joey and Rachel storyline in Friends almost never happened, though, because of Matt LeBlanc's objections to the pairing. LeBlanc was so certain in the character he portrayed, stating that Joey is loyal to his friends above everything and would never pursue Rachel because of her past with Ross. It took some convincing for the storyline to go ahead as a lot of the cast were also opposed to the idea. Only once it was stated that Joey and Rachel's relationship wouldn't actually last did LeBlanc agree to it.
This storyline, however, did end up marking a huge turning point for Joey's character in of maturing. Joey had been characterized by his womanizing ways until that point, yet he ended up really falling in love. Not only that, but falling in love with a pregnant person carrying someone else's child. Seemingly, then, Joey was prepared to take on the responsibility of raising a child for the woman he loved, which is a far cry away from the player he had always been in Friends.
This controversial Friends storyline also provided some now-iconic comedic moments. Despite Ross giving Joey the OK to pursue his feelings for Rachel, upon seeing them together Ross becomes evidently uncomfortable. Ross attempts to overcompensate for his discomfort by inviting Joey and Rachel to a dinner party with him and his girlfriend, Charlie in ''The One Where Ross Is Fine''. This episode showcased the classic meme of Ross repeating ''I'm fine'' as he was stress-making margaritas, creating one of the shows best moments.
Inevitably, Joey and Rachel discovered they were incompatible and decided to go back to being just friends, thus allowing for Ross and Rachel to be the show's long-awaited endgame. The Joey and Rachel storyline in Friends caused controversy for betraying the ideals of both characters, but it did at least provide some legendary comedic bits, and allowed for the personal growth of one of TV's most famous sitcom characters. If LeBlanc had opposed it more strongly, perhaps audiences would never have gotten Ross' now iconic and chaotic dinner party.