According to Nagual Juan Matus:

“Dwelling upon the self too much produces a terrible fatigue.  A man in that position is deaf and blind to everything else.  The fatigue itself makes him cease to see the marvels all around him.”

The Lesson:

The “self” Don Juan is talking about is the social self of bodily ego that is self-enclosed with considerings about who among other bodily egos is looking up to the self or looking down on the self, attracted to the self or repulsed by the self.

Flyer-ridden Normals are spiritually blind and insensitive because they are alternately arrogant and anxious, certain and uncertain, within the sociology of their physical selfhood.

The Flyer sucks up all the personal energy from all the considerings and worries of a mechanical pseudo-free “Normal” human being.  People have no magical awareness or follow-through because they are obsessed with their meaningless crap, both in isolation and toward one another.