I suppose that the biggest regret of people who go to Hell will be their rejection of God (John 12:48). Satan has done an amazing job by cloaking the minds of men with unbelief, so that the saving power of the gospel cannot get though to them (Romans 1:16; 2 Corinthians 4:3-4). So the people who end up in hell, will have all of eternality to lament their choice of rejecting God (Luke 16:22-31; Revelation 14:9-11).
No one can help or rescue the lost because they died in their sins, thereby sealing their fate (John 8:21). The reality of Hell is something man must face now because after death, it will be too late. Just look at the graveyards—they are full of people who once were alive just like you and me but are now dead and their deeds do follow them (Rev. 14:13, 20:12-13). If you could talk with a lost dead person, he would tell you to obey the Lord, so you don’t end up like him (Luke 16:27-28). A dead person would also tell an atheist that there is a God and there is a hell! (Psalm 14:1; Mark 9:42-48).
Hope to hear from you or see you at the services.