Music

Why do people become obsessed with music? What is it about a song that makes a human being respond? There are so many different forms and styles of music. Why do some people respond to totally different sounds but with the same emotion level. I don't have an answer to any one of those questions. But I do know that, like most people, music affects me very strongly. I can be completely happy and suddenly become completely depressed in a matter of seconds depending on the four right chords. What is it that makes music so poweful?