Because

1) I enjoy creating atmospheres and emotions with music and words

2) I want to share my thoughts and feelings with the world

3) I am a creative person and I would feel I'm letting myself down if I didn't use my creativity

4) Songs mean a lot to me and I'd like to be able to do for someone what some songs have done for me (ie helped me, gave me hope, made me feel positive about life, allowed me to express and get rid of my anger or my pain etc)