In 1909, Geoffrey Ingram Taylor, a British physicist, devised the famous Double Slit Experiment and began a revolution in the way we view ourselves in the universe. The bottom line of his experiment was that the mere presence of consciousness in a room- people- affected the way the quantum particles (the stuff the world is made of) behaved.
On February 26, 1998, Taylor's experiment was repeated by scientists at Israel's Weismann Institute of Science. Not only did they confirm that our world is affected just by observation, but they discovered that "the greater the amount of 'watching', the greater the observer's influence on what actually take place."
The most important advice I can give to a Yogi on the mat and in life is to pay attention.