Piano has helped me in patience. I am very impatient, and the piano helps me get my impatience under control.
Also, when angry or sad, I turn to the piano. A friend of mine recently died, and I found myself constantly at the piano, and yes, it did make me feel better. As for anger, most times when I sit down angry, by the time I finish a piece my mind is clear, and I feel rather peaceful.
Goals. Studying piano, I decided to make my goals like reaching for the stars. I would grab up a piece years ahead of my level, and tackle it. This helped me realize how important goals in life are, and that whatever you want to do- if you want to do it badly enough, you can do it.
If you are a teacher, teaching piano. Teaching piano gave me A LOT of confidence in myself and around people, as well as in conducting business with adults.
I think piano is quite beneficial to learn. It has benefited me in many ways other than just in learning and studying music.