Luffy is a serious person when relatives and friends. are in big trouble as well as great luffy was able to make the team members become compact although enemies encountered are at the top level, for example, a classmate of youngko (the Emperor of the seas).
The figure who is known to have a stubborn character it does not think long to face his enemies. Power increased while luffy's enemies began to make his friends hurt feelings. I think luffy strong determination to make crew members so add excited in reaching his dream of each .