Why is change in the Christian life not about giving up things you love?
Discipline matters, but transformation changes desires rather than merely removing beloved habits. Paul teaches that believers are debtors not to the flesh; living after the flesh brings death, while putting to death the deeds of the body through the Spirit brings life. God changes appetites, so old loves become hated and new loves replace them.
Les explains from Romans 8 that believers are debtors not to the flesh, to live after the flesh. If they live after the flesh, they will die, just as God warned Adam and Eve; but if through the Spirit they mortify the deeds of the body, they shall live. So the Christian life does involve discipline, but Les stresses that you aren't going to give up things you just love, because the things you once loved you begin to hate and vice versa. It is not a matter of giving it up, but of having a change of appetites.