One of the purposes of self-denial is the death of our sick self, the selfish self.  We need to die before we die.  Baptism calls for it.  When the sick self dies, God gives us back a new healed self.  Paul called it sanctification.  Jesus called it losing yourself and finding yourself.  The self centered on itself  ends in spiritual and emotional sickness.  Self-denial is the path to health and wholeness.

Do you not know that all of us who have been baptized into Christ Jesus have been baptized into His death?” (Romans 6:3 NASB)