Obstacle: Friendship
Have you ever lost any friends or family? Have you ever got into a fight so bad, that your friendship was ruined? Well, this happened to luffy, him and his sniper, Usopp, were fighting over their ship because the Merry Go ( The ship ) was unable to sail any longer and they desperately needed a new ship.
The two sides were disagreeing with each other and they decided to solve their problems by fighting. If Usopp won then the crew would sail on Merry Go and If Luffy won, then Usopp would leave the crew and they would have to find a new ship. Obviously luffy won and Usopp left and the rest of the crew accepted Usopp's decision.
During the fight, Usopp faked coughing blood and Luffy stopped fighting ( he was concerned for his friend ) but Usopp then told me that he shouldn't be feeling pity for the enemy. As much as the crew wants to help the now Ex- crew member, Sanji, the cook, stops the ships doctor by saying that it's wrong to show pity on the loser of the duel. Luffy, Chopper ( the doctor ) and Nami ( the navigator ) all cry over the loss of their crew member. Luffy crying shows that he really did truly care about Usopp and he was upset about losing not a a crew member but a best friend.
BUT.... They eventually made up, just as the Strawhat crew is about to Leave, Usopp screams for his crew to stop but they don't and instead Luffy grabs Usopp and brings him on board, both apologising to each other. This is what most people call a real friendship, the crew gladly accepts Usopp back into the crew and they set off to the New World.
Well... Something they could of done were talk it out instead of fighting to almost death. They could of talked it out and listened to each other's point of View before deciding to do something stupid. If Usopp and Luffy listened to each other and talked out their disagreement, then probably Usopp and Luffy did'n;t have to fight and Usopp would leave the crew and Luffy would go the other way with the rest of his crew and find a new ship.