I define mindfulness as the practice of being fully present and alive, body and mind united. Mindfulness is the energy that helps us to know what is going on in the present moment. I drink water and I know that I am drinking the water. Drinking the water is what is happening.
Mindfulness brings concentration. When we drink water mindfully, we concentrate on drinking. If we are concentrated, life is deep, and we have more joy and stability. We can drive mindfully, we can cut carrots mindfully, we can shower mindfully. When we do things this way, concentration grows. When concentration grows, we gain insight into our lives. The principle of the practice is simple: to bring our minds back to our bodies, to produce our true presence, and to become fully alive.

Thich Nhat Hahn, The Moment is Perfect