Ch'an aka meditation is an arduous process of ego exhaustion.

Ego is actually a derivative of our true nature, sadly, ego is our "best friend forever" as we are super-glued to it since begin-less of time.  It is a daunting task to recognize our ego, occasionally we do have a glimpse of its activities and it is ugly, but without knowing it is the sweet beacon of our true nature trying to shine through, we discarded the precious moment and told ourselves "that beast is not me!", instead of keep working with that simple awareness, we yield to our cunning ego one more time.  

Watch out! Ego is our true nature "being misused", "in camouflage"..., it is clever and versatile. Let us face it, it gives us an additive layer of snugly warmth and worse - a false sense of  fearlessness(because the ego completely took over) whereas true nature is totally passionless, unattractive, foreign. 

The magic of Ch'an is "greet the ego and sit it out", after all, ego is where the Truth lies.