What defines joy?

I would say..

A good piece of music that suits ur mood right at the very moment.. =)

Another reason for why I love music so much..

Music has always been there since the first human civilization..

so u can guess that it does play an important role. hahaha

No hate. No sorrow. Love and Peace.

I believe everyone knows John Lennon quote on Happiness being key to life..

When I was 5 years old, my mother always told me that happiness was the key to life. When I went to school, they asked me what I wanted to be when I grew up. I wrote down ‘happy.’ They told me I didn’t understand the assignment, and I told them they didn’t understand life. -John Lennon