In order to use Zen ideas to get at the heart of your suffering, it is important to look at yourself. You don’t have to spend all day looking in a mirror. You have to spend your whole life looking at a mirror. That’s how important self is. According to Buddhism, the main cause of suffering is ignorance. Ignorance, in Buddhism is different from regular ignorance. Regular ignorance is a general lack of knowledge or understanding. If you suspect that you are ignorant in a regular sense, then you will suffer because you find yourself lacking important qualities. Ignorance in Buddhism is specifically a wrong understanding that your self exists as an independent entity. There is no shame in Buddhist ignorance because it is the basic human condition. It leads to all other suffering like the suffering of regular ignorance, loneliness, disconnectedness, shame, anxiety and/or depression. That is why the idea of self is so important.
It is completely impractical to spend your life looking in a mirror. As you inquire into your self, you have to be ready to challenge the very idea of self. You can also challenge the idea of mirror. Your self is so important that the whole world is a reflection of you. With that kind of mirror, you have no choice but to spend your whole life looking at it. Anywhere you look, you encounter a reflection of yourself. Even if you close your eyes and look at your thoughts you see yourself there. Your parents, friends, children, and pets, as you experience them, are reflections of you. When you see your image in a mirror, that is also you. Wherever you look, if you like what you see, you are liking yourself. If you hate what you see, you are hating yourself. If you are suffering, you can look to yourself to see why you are suffering.
When your idea of self expands beyond the image in the mirror to include the mirror, the frame, the wall, your family, and the world, you will gain a better appreciation of how important you are. You will see your self as an integral part of all that is happening around you. Experiencing your connectedness to everything brings with it a sense of humility. That humility is your important self getting out of the way. The suffering goes with it.

