TIL The writers of 'Friends' didn't originally intend for Joey to be dim, but when LeBlanc auditioned for the role, he put a "different spin" on the character, convincing the writers that his being dumb would be a great source of comedy.

Super common in almost all shows that run too long, specifically sit-coms.

Writers are told what viewers like and think is funny about the character, so they write it more like that...and more...and more...and eventually, over the years, they turn into a parody of what they were originally.

You're right. Joey started out as a completely normal functioning dude, who was a little slow, and under-educated (which he at some point said he dropped out of high-school); but again, normal dude for someone who didn't finish high school. Which made the group more realistic.

He got worse and worse, and by the end he was functionally retarded. He didn't get the most simple concepts, the whole french thing, it would take him 30 seconds to get a joke everyone else got instantly, he'd get lost on the way to his apartment.

Same thing really happened with every other character. Chandler went from being the "funny guy", to literally all he did in the last 3 seasons was make dad jokes about being afraid of Monica. Monica was a little neurotic at the start, and ended with clinical OCD. Phoebe was a little weird at the start, if it was today she would have been the hipster of the group; not uncommon...by the end she was a nutcase that had committed all these crimes in her life, and always had to add something insane to every conversation.

Really the only ones that stayed normal, for the most part, were Ross and Rachel...but that's just because the writers had so much relationship stuff to write into the characters.

/r/todayilearned Thread Parent Link - en.wikipedia.org