Neptune represents our subconscious mind. It is associated with dreams, inspiration, psychic receptivity and illusion. It is also associated with intuition and spiritual enlightenment. It is also a planet of mercy and compassion. In your chart, if Neptune is well aspected will indicate a great inner sensitivity, to manifest dreams and become highly creative. Negatively, it will indicate deception, deceit and addiction.
Neptune Square Midheaven
This aspect can indicate extreme insecurity and self-doubt, unless your parents and other influential adults make a special effort to reinforce your self-confidence. When you meet a difficult person or an obstacle, your first tendency is to run away, because you feel that you cannot overcome it. This is probably not true, and you must learn what you really can do, instead of limiting yourself to the few tasks that you are not afraid to do. Sometimes you seem to be surrounded by energies that are very weakening, usually from people you are with who give off very negative energies such as resentment, hostility or anger. You don't attract such people to any unusual extent, but you suffer more than others from being around them. As much as possible, you should associate with positive and optimistic persons. This empathy has a positive side, however, in that you understand other people very well, knowing what is going on in their minds as well as what they say. But it will take you a while to learn how to interpret the signals you get from others. While you are young, you may frequently misinterpret people. You will feel a need to work for an ideal that is higher than yourself or for a person whom you can idealize and respect. This is fine, but you will probably be taken advantage of by people who are unworthy of your devotion, unless you work very hard to get past your idealizations and see who they really are. Then you can choose intelligently.