Music can help you through any kind of emotion. It can help you through a break-up, make you dance, or help you realize or understand something about yourself... and if I can sing a song and make someone feel those things then I will feel like I have made a difference.
It's a very big mental game, all day leading up to warm-ups. You're not sure if your curveball will break, or will you be able to throw it over the plate? It's all negative thoughts going into the game.