Yet many outgoing people are still primarily self-centered. Whether a person is bold or shy makes little difference if that person's energies are being consumed, enhancing or protecting his own self image. He does not need to protect himself. He can be busy giving himself to others. A second personality trait in a good missionary is a high tolerance for ambiguity.
People see and do things differently.
Beyond that, you will learn totally new cultural values and apply those values while you are in your new culture. That kind of an adaptation will help you to choose a course of action more similar to one that people in the culture would choose. It will also free you from exhausting frustration of either trying to change things or trying to suppress your own ideas. Not only will people have different personal and cultural values, they will also hold different doctrinal positions. You will be faced with the tensions of deciding between what you believe to be correct doctrine and the unity of the body.