Anime filler episodes get a worse reputation than they deserve — I'd argue a well-placed filler arc can deepen a cast more than three canon chapters ever do. I rewatched Naruto's 2004-2005 filler stretch last year and, honestly, the Kakashi mask episode did more for his character than most of the war arc. But I also dropped One Piece around episode 300 because the padding between manga beats stopped feeling like story and started feeling like a hostage situation. So is filler a legitimate creative tool, or just a scheduling crutch studios use to avoid catching up to the source material?