If it didn't, we would be in one sorry situation. I don't know what the secret of true happiness is - if I did, I'd shout it from the rooftops. I don't know why some live in joy and others live in misery, but I don't think it has as much to do with what kind of a person you are as some people would like to believe. You start out pretty much like everyone else. You're happy with your toys and your Casper doll.
Youth brings education, and education brings dreams.
For most of us, anyway. Adulthood sets in, like a dry rot not noticed until fully in place. There are things in your life that stick out, things you're not sure how to deal with. Enlightment seems beyond your grasp, because your hands are too filled with the things of the world to clutch at wisdom. Ennui can set in.