Because it's a medium. A medium for everything and it is one of man's most stimulating and powerful tools. Music can be a means to express, communicate, absorb or relieve.
The person who asked this utterly foolish question must be an idiot.
Haven't you ever wondered why people do things? I think about stuff like this all the time, i was just asking for the opinions of others, why do you enjoy music, do you crave the awesome shiver that goes down hour spine when you hear a part of a song you really like or do you like it cause it changes your mood? Have a go and answer the question