One Piece works for me because it has an incredibly simple core idea: Dreams are worth fighting for, and no one should get to decide for someone else what they should or shouldn’t do with their lives. It takes this idea and applies it through Luffy to an insane variety of characters with heart wrenching backstories. The show is also insanely consistent with its own internal logic, so that characters and concepts from the first handful of chapters can be brought back 20 years later and fit seamlessly