One: Piece Episode 235

The argument escalates until Luffy, in a moment of frustration, almost tells Usopp to leave if he doesn't like the decision. Though Luffy stops himself, the damage is done.

Usopp, who has a deep personal bond with the Merry, refuses to accept this. He accuses Luffy of abandoning their "comrade" for a newer model. One Piece Episode 235

Usopp officially declares he is leaving the Straw Hat Pirates. He challenges Luffy to a duel, with the winner keeping the rights to the Going Merry. The argument escalates until Luffy, in a moment