The adult part of our human nature has executive powers to "put plans, actions, or laws into effect." The ideal is for the adult to be and act intelligently, rationally, and reasonably, in a word wisely. This is also the ideal of the parent state but it is influenced significantly by the parenting received as a child so thinks and acts from past learning and experience. The adult is anchored in the present so decisions and actions are unprejudiced by the past.
For example the parental part of us might look upon co-workers in the middle of a project amidst a sea of clutter and think "This is outrageous, these people need to clean up this mess and or they won't get anything done! The adult (and wise parent/leader) focuses on results so has less concern about the process used as long as progress is made and goals are achieved.
We use our adult abilities to reason, organize, evaluate experiences, and gather information to help us be adaptable to situations, make the best decisions, and take appropriate actions. The adult deals objectively with life based on education and experience to avoid problems and mistakes and achieve success. It's never too late to add to our education and seek meaningful and useful experiences.
We need to take care our best
choices aren't contaminated by our parent, child, or "lower" life form
(lizard brain etc.) energies, but also keep open to valuable input from these
energies as well. Here an inner child might cause problems by being selfish or
withdrawn, or conversely give us extra energy and enthusiasm to lighten our
load and keep a lighthearted perspective. The downside of the adult state could be that it lacks these positive attributes, so can act overly rational and under emotional like Spock from Star Trek.
The key is to recognize these varying aspects of our True Self and welcome them to be an active part of us whenever they are needed. We are wise to hold each one gently but firmly so none of them takes over and denies the others, or jump from one to another wildly and uncontrollably. For each there is a time and place. There is no guideline or rule, but a balance of head and heart with a deep knowing which is right and true in each moment to allow appropriate expression of the total personality.
One of the great benefits of a strong adult state is to act as a go between or referee between our various selves and pull from the best of each while avoiding their downsides. We then find we can be as natural as an animal, playful as a child, smart as an adult, and nurturing as a parent all at the same time. The key is as always to first be aware, then come to really know and love the different parts we play, and know they are all a part of us in an ancient, deep, and real way.