You have issues with power and control, and specifically, you may have experienced responsibilities thrust upon you without being given the attendant resources needed to fulfill them. You may be drawn to organizations with a rigid hierarchical power structure. At times, you're more likely to operate from your subconscious power issues by trying to control or manipulate others into doing what you want.
Mental rigidity and stubbornness are another sign that things are askew in your field of control and power. Learning to recognize these symptoms will help you balance yourself, thereby enabling the serious and realistic attitude that comes so naturally to you. Remember to delegate. You don't have to do everything yourself.