Joy or Happiness?

At our weekly Bible study last night, we were presented with the question of what our "joy" level is right now. I explained that for me, I define the term joy differently than many other people probably do. I see joy as a constant in my life. I equate it with a sense of contentment, peace and comfortableness - in fact, I like to think of the Hebrew term shalom here. For me, the joy I have comes from God and it's the knowledge that Christ is my redeemer and that in him, I have an advocate. I get a sense of completeness from this and I know that ultimately, "things will be alright" because of this. I believe it is the sort of peace that Paul writes about which surpasses all understanding and which guards our hearts and our minds in Christ Jesus (Phil. 4:7).

I think this is different from many people who equate joy with happiness. I see happiness as an emotion - something that comes and goes depending on circumstances. But the joy that I have in knowing Christ is the savior of the world in ongoing and cannot wax nor wane. It's true that I might not always be happy, but I am always joyful because Christ is always part of my life - and nothing can take that away. I always have a sense of joy, whether I'm happy or not. Joy is a state of being, not simply an emotion - at least, that is what I think.

I'm not sure this is easy to understand - some in the Bible study group grasped immediately to the concept and understood well, while others couldn't quite wrap their minds around this differentiation. What is your sense of joy and happiness?