The worst part about life is knowing that you missed an incredible opportunity to experience the love and power of God. Those who come to that realization do so when they are ensconced in hell and no longer have the opportunity to live a different life. The knowledge of what could have been and can be is hidden to all but the genuine seeker.
A genuine seeker is anyone who desires to have a relationship with God on His terms. They know that life as they know it is less than ideal, that they have made mistakes, that they have reneged on promises and been betrayed, and that they yearn for a different day, and a different tomorrow. They also know that when the sun sets at night, they are rarely, if ever, satisfied with how they lived that day. So, for them, choosing a relationship with God is "a no-brainer."
While it is true that they might need to live somewhat differently, the benefits gained from their new life far exceed any supposed "losses." The cost-benefit analysis is heavily weighted on God's side. If for any reason they later decide that they no longer want to have a relationship with God, they can be confident that hell awaits them.