Acharya Prashant explains that humans have a long-standing habit of equating consciousness with thinking. Because of this conditioning, when people are asked to pay attention or watch their thoughts, they often introduce an additional thought about 'watching,' which only increases mental activity and gives more energy to the existing thoughts. He clarifies that true attention or watching is not a mental activity or thinking; it is simply being aware of the thoughts that are already present without adding new ones.