The Bible teaches us that we, having been justified by our faith in the sacrifice and resurrection of Jesus Christ, now have a new nature in addition to the sin nature we have always had, now often referred to as the "old nature".
Living according to my old nature, I could be found happy, excited, and content at times or sad, angry, and discontent at other times. My old nature sought solutions to discontent from sin or, at least, from a sinful perspective on life. In fact, it is clear to me now that God used my discontent as part of his plan for leading me to knowledge of and faith in Christ. But, having assumed (quite ridiculously, now that I think about it) that the happy times I experienced with only a sin nature were not necessarily sinful in nature, I have been trying, in the course of my "new" Christian life, to find contentment by reproducing or replicating the circumstances or attitudes that seem to have led to contentment in my "old" life.
So, I now have a new nature. But I sought solutions from what satisfied my old nature. Not only do those 'solutions' fail me now, but because they come from a perspective informed only by a sin nature, those solutions are necessarily sinful, even if they don't include any of the "big" sins like murder or adultery. The Lord is our refuge. All else is idolatry.
This in spite of the many occasions in which I have reflected upon my former way of life and wondered, "how could I ever have been satisfied with that or found pleasure in it?" The simple answer is: ignorance is bliss. But, I refuse to believe that knowledge is angst. Paul addresses all these things thorougly in Ephesians.
"So I tell you this, and insist on it in the Lord, that you must no longer live as the Gentiles do in the futility of their thinking. They are darkened in there understanding and seperated from the life of God because of the ignorance that is in them due to the hardness of their hearts. Having lost all sensitivity, they have given themselves over to sensuality so as to indulge in every kind of impurity, with a continual lust for more.
You, however, did not come to know Christ that way. Surely, you heard of him and were taught in him in accordance with the truth that is in Jesus. You were taught, with regard to your former way of life, to put off your old self, which is being corrupted by its deceitful desires; to be made new in the attitude of your minds; and to put on the new self, created to be like God in true righteousness and holiness." ~Ephesians 4:17-24
I had some time ago memorized these passages and believed, until now, that I understood them well. Yet I learn. Contentment can be found niether from our old life nor from our old way of thinking. And, true knowledge does not result in angst or fear. In fact, Paul prays that we will have knowledge and he tells us it is precisely so that we may have not fear, but hope.
"I keep on asking that the God of our Lord Jesus Christ, the glorious Father, may give you the spirit of wisdom and revelation, so that you may know him better. I pray also that the eyes of your heart may be enlightened in order that you may know the hope to which he has called you, the riches of his glorious inheritence in the saints, and his incomparably great power for us who believe." ~Ephesians 1:17-19a