According to Compassion.com, Happiness happens to us. Even though we may seek it, desire it, pursue it, etc., feeling happiness is not a choice we make. Joy, on the other hand, is a choice purposefully made. Joy is an attitude of the heart and spirit, present inside of us as an untapped reservoir of potential.
Happy means something had to happen for me to be happy. Happiness is temporary and you have to pursue or do things that will make you happy. Happiness is determined by your circumstances.
On the other hand, Joy is a choice and it is not determined by your circumstances. I could be lacking in all areas of my life, but I can still have Joy because my circumstances don’t control my attitude, my heart and spirit.
I would rather have Joy than happiness because things come and go. There are ups and downs and life but if I have Joy; than no matter my circumstances I will still have happiness/gladness.