SELF-CONTROL is otherwise known to KJV Bible readers as TEMPERANCE. As the term suggests, it is about exercising control over self - which consists of our feelings, thoughts, appetites, drives and will.
The Apostle in Galatians 5: 23 did not advocate that self-denial - denial of feelings, appetites and drives but rather the exercising of control.
Control does not mean total disuse, but rather a regulation of use. It requires knowing when to permit partaking in a pleasure, activity or a state and when to restrict self from indulgence.
For example, our sexual feelings have been given to us by G-d both to populate the earth (Genesis 1:28) and for enjoyment and pleasure (Proverbs 5:15-19; Proverbs 30:18-19 and Songs of Solomon). The appetite for food, has also been given to us by G-d (Genesis 1:29). Our desires for responsibility and power are also given to us by G-d, who designed us all to be rulers over his domain on earth (Genesis 1:28).
Nothing is wrong in these appetites of themselves. What is wrong is how we use or misuse our drives and appetites. Do we use them to fulfil the purposes of G-d? Or do we let these drives violate G-d's original intent, will and design for us?
Even our personality traits and temperament may be designed in order for us to achieve a G-d given role or purpose. I believe that G-d puts in every individual that he has created a little of himself that we all collectively manifest G-d (Genesis 1:26). Individually, we just manifest only a particular trait or DNA of G-d. Collectively, all human beings could represent the entirety of G-d characteristics and traits. Hence even our psychological make up could represent a part of G-d that no one else has. As such, nothing that we have are evil of it self, but rather, what constitutes the self requires right alignment with G-d purposes and will.
For example there is the account of Levi and his descendants. Levi's short temper was cursed by his father, Israel or Jacob (Genesis 49:5-7). Yet his descendants were chosen to be G-d's priests because of this trait that led them to be intolerant of unrighteousness. Levi was redeem through men like Moses and Phineas, who both had zeal for G-d and for seeing his will executed, even if it meant slaying others.
G-d has also left us with the model example of JESUS, who did not deny his feelings when he was in the garden, where he wanted the cup to pass (Matthew 26:36-42). Yet Jesus submitted to G-d's will even though he felt troubled at the thought of crucifixion.
Finally, I leave with this beautiful text (Phillipians 2:5-8; The Holy Bible, English Standard Version):
5 Have this mind among yourselves, which is yours in Christ Jesus,  6 who, though he was in the form of God, did not count equality with God a thing to be grasped, 7 but made himself nothing, taking the form of a servant,  being born in the likeness of men. 8 And being found in human form, he humbled himself by becoming obedient to the point of death, even death on a cross.
Align thyself with the will and purposes of G-d!