Writing is a process that institutionalizes your broken thoughts into complete ideas. It gives life a meaning that prevents burnout, boredom and other sorts of cimmerian darkness. Moreover, it's good for you! It builds healthy self-esteem which automatically enhances your confidence in all other areas. Writing is a 'characteristic' movement from fear to confidence, from difficult to easy, from incompetence to competence. There is a reason why legends had advised to maintain a personal diary. Writing activates the second tool of comprehension; reading being the first.
Have a problem? Write it down. You will come up with a better solution. Have a crush on someone? Write about that person. You will be able to express better (and may become a chic magnet) A good sonnet becomes an extraction of intense feeling from the ore of emotions (try poetic flirting). You will possess the art of persuasion with delicacy.
It will help you to clarify thoughts about love and life, about right and wrong. Writing is directly proportional to thinking. The better you write, the better you observe. The better you observe, the better you think.