Jeez. Why? I mean that sounds like a stupid question. But what could they talk about for that long in a series?
Captain Moran Arc: Show starts
Buggy Arc: Zoro joins Nami partners up
Kuro Arc: Usopp joins
Don Krieg Arc: Sanji joins
Arlong Arc: Nami joins
Buggy Side Story Arc:
Loguetown Arc: The story of the show's title One Piece
The Warship Island Arc: anime only
Reverse Mountain Arc: start of Grand Line story
Whiskey Peak Arc: Meet Vivi which preludes to Alabasta
Koby/Helmeppo Side Story Arc: returning characters from the first few arks in their marine hijinks.
Little Garden Arc: A character gets sick
Drum Island Arc: Tony Tony Chopper joins and they try to save the sick character
Alabasta Arc: Vivi leaves the group, Crocodile is the villain
Post Alabasta Arc: Nico Robin joins
Goat Island Arc: comedy anime only arc
Rainbow Mist Arc:
Jaya Arc: prequel to Skypiea Arc:
Skypiea Arc: Take on someone called God who lives in clouds where everyone has wings
G8 Arc:
Davy Back Fight Arc: short comedy arc
Ocean's Dream Arc: Memory loss short mini arc
Water 7 Arc: Franky Joins
Enies Lobby Arc: Rescue Robin, Robin's backstory and she truly joins the team no more doubts Luffy starts declaring war on the world government and bounties skyrocket from here on out.
Post-Enies Lobby Arc: New ship
(going off of memory now... my cheat sheet is finished)
Thriller Bark Arc: Beat up the first Shikibukai (1 of 7 Warlords that rule the world)
Luffy ends up in an underwater prison fighting to save someone from the most secure prison in the world
There's a huge war that shakes the world,
There's a section where everyone gets separated and everyone learns new tricks and then meets up years later Usopp being buff all of a sudden, as an example. Luffy has a giant scar. Some pivotal characters die world gets thrown into chaos.
They go underwater and have a huge arc biggest to date.
An arc where they are an Island called Punk Hazard destroyed by a biological explosion.
Then I didn't get around to keep watching it. Gotta get back to it.
They still have to resolve things with Shanks, the rest of the Shikibukai, a whole bunch of other characters have to be resolved and will be....
Series probably going to end up being 1k episodes. I mean they just introduced in the 600's Luffy's childhood friends in his backstory, and they haven't appeared in the story for decades, so who knows what rabbit hole they are leading the story down.