There are many reasons for soul dissatisfaction. But one of the main reason is pride.
Not just any pride or arrogance, but;
Pride through Experience.
Pride in Theology.
Pride in Self-sufficiency.
The older brother in the parable of the prodigal son, a valiant commander of the Aramian Army named Naaman, and the rich young ruler who came to Jesus asking how he can obtain eternal life exemplify these three kinds of pride that causes us to miss the very heart of God.
All three appear to have their hearts in the right place, but all missed the heart of God because of soul dissatisfaction. The older son was "obedient" to the father; Naaman came to God of Israel for healing; and the rich young ruler, despite all he possessed, knew he did not possess what mattered the most--eternal life.
The error of the older son is that he failed to know his father's heart by assuming he knew it all. He was the obedient, good son. And yet how sad to see his father pleading with him because he can't stand to witness his father's amazing mercy to his returning younger brother. We want mercy for ourselves, but judgment for others...
From this parable, we can see that both sons were soul dissatisfied. Just because we attend church and all the meetings, does not guarantee we are soul satisfied. It is within a relationship with God that we will find satisfaction for our souls.
Naaman expected Prophet Elisha to perform some amazing, tangible ritual to heal him of his leprosy, but instead was told by a messenger to do something seemingly absurd. Hence, his first reaction was of anger, just like the older brother in the parable.
Our pride in our theology - i.e., our understanding of how God should work - often gets in the way and is one of the major signs of our soul dissatisfaction. Remember the story of Jim Elliot and his four companions who were killed during their mission service in Ecuador. Their deaths seem in vain and horrible, and you can argue God could have used these dedicated young men for His service in far more powerful ways, but because of their martyrdom, youths all over the world were ignited and inspired for mission.
God does not work in the way we deem appropriate or ideal, for His ways and thoughts are infinitely higher than ours.
The rich young ruler was not denied eternal life because he was wealthy, but because he was self-sufficient. He did not "need" God as he claimed. That he could not let of his wealth and possession betrayed his holding on to self-sufficiency.
As Oswald Chambers said, if you are going to ask God, be sure you first need Him.
Blessed are the paupers in the spirit, theirs is the kingdom of heaven...
--from Nakwon EM June 17th Sunday Worship Service