Well said:
So here’s my theory: I believe that introducing visceral elements into an app will take it past the point of just being awesome. It will make your app speak to the subconscious, built-in affinity that humans have for the physical properties I mentioned before. I believe that even if you designed the most perfect and useful app possible, that the act of adding in these visceral elements will make people love your app on an even deeper level.
Via Daring Fireball