Well, it's not my description. But it's one that widely accepted. My own take is that our advanced cognition makes up what is 'being human'. Unlike animals we don't just do stuff 'because we like it', we have motives that go beyond instinctual needs/urges. We have a more complex thought process behind every action, and it is this advanced cognition that has led humans into the ultimate being of destruction, because we're totally and utterly incapable of grasping why we've evolved to the point we've evolved. We are utterly unhappy with the state of being, deep down, because we haven't the faintest clue why we can comprehend things so vividly, and there's no concreteness in the world around us that can explain.
Once again I feel that it misses the point when people go "Oh, spirituality, I like taking a shit and it feels good - is that spiritual then?". Sure, if you genuinely feel that you gain something, if you feel that it gives you a sense and a purpose, if it makes you feel at ease with your existence then sure. It's spiritual. To me, the spiritual would be anything that connects me to the world around me without feeling like a stranger in it. Without feeling like an external being. An abscess.
Also I find it funny when people say "Oh we just do stuff because we like it", right... I don't know about you guys but I'm not that instinctual. I think more than I do, and I spend most of my time thinking about what I do. I exercise not because I feel a strong urge deep down to do so, I do it because I've connected the dots between what sort of activity makes me feel good, and what I am capable of doing. You could let a dog run up and down the same field for its whole life and it'd be content. I wouldn't.