It is a pleasant thing to feel good, and we do well to give thanks for the times in life when God blesses us with spiritual, emotional and physical tranquility and pleasure.
However, if feeling good is established as the goal of life, we will discover that a cruel and destructive tyrant has taken control of our existence. God has not determined that we are to always feel good in our present existence. Sorrow, pain and discomfort are necessary components of life in a fallen world wherein resides a fallen devil and fallen human flesh (including our own). Feeling good all the time would deceive us into believing that a dying planet can be the home of our hearts. It cannot, and let us thank God that He lovingly promised sorrow to Adam and Eve as a means of arresting their attention - and ours - to the need for redemption from a world that "lieth in wickedness" (Genesis 3:16-17; I John 5:19).
"If ye then be risen with Christ, seek those things which are above, where Christ sitteth on the right hand of God. Set your affection on things above, not on things on the earth. For ye are dead, and your life is hid with Christ in God" (Colossians 3:1-3).
The born again believer would not want to feel good when he is disbelieving and disobeying God (Psalm 51:17). He would not want to feel good in times when God brings portions of sorrow and difficulty as the necessary preparation for ministry to others (II Corinthians 1:4). He would not want to feel good when the Holy Spirit is pressing his heart with the lostness of unbelieving humanity, or the waywardness of a fellow believer (Romans 9:1). He would not want to feel good when considering brothers and sisters in Christ who are being persecuted, imprisoned, tortured, and martyred for the Lord Jesus (Hebrews 13:3). And he would not want to feel good in those times when he is remembering the cross of his Savior, and the agony, forsakenness and death experienced by the Lord Jesus in His sacrifice for us (Isaiah 53:3).
Accepting the fact of sorrow, pain and difficulty as necessary components of life in Christ is a fundamental lesson of genuine godliness. This does not preclude pleasure, of course, nor does it mean that life will always be filled with pain (although let us remember with much reverence and prayer that some brothers and sisters are called to a life of continual hurt whereby God is glorified in a most special way as they faithfully trust and submit unto Him). It does mean that it is necessary that we are to not always feel good in our present life. Our Heavenly Father loves us enough to include sorrow and pain if we are thereby drawn into a greater experience of Him, and prepared to walk with Him in godliness and ministry to others. Perhaps most of all, suffering can lead to a greater identification and likeness to the Lord Jesus. Conformity to His image is our Father's ultimate purpose in our lives, and we shall discover that growing likeness to Him is the joy of our hearts, even if our souls and bodies do not always feel good in the process...
"Always bearing about in the body the dying of the Lord Jesus, that the life also of Jesus might be manifest in our body. For we which live are always delivered unto death for Jesus' sake, that the life also of Jesus might be made manifest in our mortal flesh."
(II Corinthians 4:10-11)