The choice is to be changed, day by day, and through prayer and Bible study to come to share the Father's heart and view of the world, or to never reach out and grasp all that God has for us. There is one deadly virus we must all guard against, however, or a successful heart transplant will fail. That virus is legalism. It closely matches sanctification in outward appearance. The difference is in motivation.
Legalism defines spiritual growth as obeying the rules.
Sanctification defines spiritual growth as sharing God's heart. I don't know if I've mentioned her before, but a little old lady from the north of Scotland made a great impression on me a number of years ago. She belonged to a strict denomination called the Brethren. She told me in all earnestness sitting at her kitchen table that God was pleased with her because she didn't go to the cinema, play cards, or do the wash on a Sunday. She hadn't actually been to church in ten or fifteen years because making the Sunday dinner for the menfolk was more important, but she didn't see any contradiction in this.