In my theory of meditation, joy is encompassed through meditation as the result of sensory deprivation. Think about it, the goal of meditation is a blank mind, nothingness, stillness. At first your mind goes crazy, but then eventually moves to calm. In providing details to our group, I instruct attendees to bring their awareness back to their bodies instead of floating around in the past or the future. To block out thoughts, use a mantra. To block out images, focus on a crystal ball or a sun or the moon. Something bright yet nondescript. I am shutting down the senses. I am in a white, soundless room.
But when you return back to your normal state by ending your meditation, it is not the same world you left prior to meditating. The pleasure of small things becomes magnified. Suddenly the sound of a bird is crystal clear and more magnificent than ever. The white clouds against the blue sky never looked so intense! You are left with a sense of joy, the pleasure of things being just as they are, but now they have become visible. Of course this fades over time, but it can be recaptured after another meditation session. Call this one of the most beneficial side effects of sensory deprivation (meditation).