Having the faith to take life one piece at a time- to live it in the knowledge that there is something of God in this for me now, here, at this moment- is of the essence of happiness. It is not that God is a black box full of tests and trials and treats. It is that life is a step on the way to a God who goes the way with us. However far, however perilous.
We know joy when we are happy to take from life what is given. When we experience the joy of the soul and higher states of consciousness, this joy is the essence of completion and fulfillment. There is nothing that can add to it or take away from it. Joy is our natural state.