Yall read 1000+ chapters of One Piece and don't know what filler is? Perfect example of filler is Yamato. Paperchampion will consider Yamato writing to be A+. Another example of filler is pretty much almost all of Egghead. Strawhats gets separated, then reunite, then separated again, then we have characters passing out because of bugs, crying asking the same question nonstop of "what happened to kuma" instead of just showing us kuma's backstory he extends it for 12+ chapters, traitor plot lasting multiple chapters instead of showing us, then have characters fight, then pass out, then wake up. Filler is unnecessary drivel that can be removed without any lost of information to the story. Not hard to understand what filler is.