Davy Back Fight
Davy Back fight by far the least useful arc in the story.... Fully supported.
the worst was thriller bark! I couldn't stand it and its setting,also the story was bad there
without kuma´s appearance, zoro´s sacrifice and the comedic relief i would have agreed on thriller bark. the setting was boring and out of place in the op world, the opponents beside ryuuma were more like a gag than serious fighters( perona, absalom, zombies etc.) and everything about the arc villain, be it his personality, his design or his strength especially as a Shichibukai, were really disappointing, but in the end i have to second davy back fight because it was just pointless.
Even though FI arc was a little disappointing i think it isn't worst than Davy Back one . So i will vote Davy Back