Prayer fulfills the need humans have for God, for inspiration, for affirmation of our own spirits. In prayer, we communicate with the essence of everything that exists, including our own essence. We have a message to share with life, with God, and we want to share it with authority. The message is coming directly from our hearts, we are talking with our divinity, with Divinity Itself. The power of prayer can lead us into love, truth, and personal freedom.
The smile of the contemplative in the presence of the Beloved is merely a physical expression of the total joy one perceives as one communes with God. St. Bernard used to say, "The joy of being in love is in the very loving." In other words, joy is not to be sought for itself, but is a by-product of love, and the smile is but the physical, exterior expression of the inner joy-love.