Mindfulness is a fortress gatekeeper- a tricky job. Sometimes it's obvious what is for the good, but a good con artist can appear beneficial, and a beneficent person might be shy, or strange. Such is our inner world. We can convince ourselves to have thoughts and actions that harm us, neglecting the beneficial ones. Training our mind to stay with objects such as breath and goodwill, we grow our capacity for concentration and insight. In this way, a good gatekeeper is a benefit to our being.