We get a sense of being a solid entity. Our personhood has definition, and our personality has edges. In addition, owning our desires and wants helps us to reach our goals in life. Realizing our desires motivates us toward any goal. Choices are the foundation upon which boundaries are built.
Choices have two directions.
We can choose to do something, or we can choose not to do it. There are certain things in life over which we have no control, but we always have a choice about how to respond to these things. Our choices determine our direction in life, but if we do not own this fact, we don't know where we are going. We resent where we end up as if it's someone else's fault. Many of us don't take responsibility for our own limits, and overextend ourselves.