We sometimes think that being mindful means being critical of ourselves and very watchful. We think that meditation provides us with a big brother who is going to watch over us or whip us into shape if we do something wrong. But mindfulness practice is not about punishing yourself when you lose track of your breath or your thoughts. Mindfulness does not criticize or set conditions for you. Nor is it about rewarding you. Rather, it is helping you to discover the alertness that already exists in your mind, by dispelling the dullness that has covered it up.
From Mindfulness in Action by Chögyam Trungpa, page 30