The cause of samsara, or ultimate confusion, is holding on to vague concepts. That is what is called fixation, or in Tibetan, dzinpa. When we do not have clear perception, we must hang on to vagueness and uncertainty. In doing so, we begin to behave like a Ping-Pong ball, which does not possess any intelligence but only follows the directions of the paddle. . . . Whatever we do, our actions are not perfectly right because, based on this neurotic game, we keep being Ping-Ponged. Although it may appear that the Ping-Pong ball is commanding the players, although it seems amazing that such a little ball has so much power to direct the players’ actions and even draw spectators to watch it going back and forth -- actually, that is not true. The Ping-Pong ball is just a ball. It does not have any intelligence; it’s just operating on reflex. . . . As the Ping-Pong Ball, you feel very dizzy and you ache all over your body because you've been bounced back and forth so much. The sense of pain is enormous. That is the definition of samsara, or confused existence.
From "Awakening and Blossoming," in The Truth of Suffering and the Path of Liberation, Pages 65 to 66.