Don’t call it the placebo effect. Call it the placebo power. (Philosophistry)

After sitting motionlessly, close your eyes. Our mind is analogous to a cup of muddy water. The longer you keep a cup of muddy water still, the more the mud settles down and the water will be seen clearly. Similarly, if you keep quiet without moving your body, focusing your entire undivided attention on the subject of your meditation, your mind settles down and begins to experience the bliss of meditation.

I like this metaphor.