Alma 37:30-31

For behold, they murdered all the prophets of the Lord which came among them to declare unto them concerning their iniquities; and the blood of those which they murdered did cry unto the Lord their God for vengeance upon those which were their murderers; and thus the judgments of God did come upon these workers of darkness and secret combinations. Yea, and cursed be the land forever and ever unto those workers of darkness and secret combinations, even unto destruction, except they repent before they are fully ripe.

If we turn away from God we know that we will pay for it with both our soul and with the pain that we suffer here on earth. Sometimes it looks like the people who turn away from God have a great life, but there is an emptiness that only God can fill. Also when the time comes to stand before him during judgment those people will be very sad with the outcome. On the bright side though, there is always the possibility that these people will come to Christ. We cannot give up on them.