Mindfulness is cultivated by assuming the stance of an impartial witness to your own experience. To do this requires that you become aware of the constant stream of judging and reacting to inner and outer experiences that we are all normally caught up in, and learn to step back from it. When we begin practicing paying attention to the activity of our own mind, it is common to discover and to be surprised by the fact that we are constantly generating judgments about our experience. Almost everything we see is labeled and categorized by the mind. We react to everything we experience in terms of what we think its value is to us. Some things, people, and events are judged as "good" because they make us feel good for some reason. Others are equally quickly condemned as "bad" because they make us feel bad. The rest is categorized as "neutral" because we don't think it has much relevance. Neutral things, people, and events are almost completely tuned out of our consciousness. We usually find them the most boring to give attention to.
Full Catastrophe Living, Jon Kabbat-Zinn PhD, pg 33