A simple answer would be something like.. Because I choose to be this way! Can we buy this for an answer.... Certainly no! Because, you are like this due to 6 major influences on you that are running your operating system. What are they.. The Environment that you are in, the behavior that guides you, the possibilities and capabilities that you see or have, you belifes and values that runs you, your Self Identity and finally your purose of Life. All these are so interlinked that a change in one level will result in a change in another and so on. So what we deduce is that by consciously working upon these logical levels and aligning them with the mission or purpose of Life we can reprogram and live a life that we wish to live.