Many people stumble along the path from birth to death with colossal holes in their lives.
They never read. How can a person know anything if he never, ever reads?
They never think.
They never work out.
They never learn to experience music or art or drama and sometimes cultivate a distaste for artistic beauty.
They are immune to spirituality, and rarely give God or questions about the meaning of life a thought.
The puzzling thing is that it's not necessary to be complete in all these respects in order to create an illusion of happiness. Many people die happy and satisfied having never done much of anything.
When you think about it, who of us really knows or understands much at all about anything? Those who take the trouble to investigate the world around them learn above all that they are ignorant and haven't a clue; that notion troubles them and tarnishes their happiness.