Psalm 40:6 (NIV)
You did not require.
A man does not need to be saved to be happy and prosperous in this life. God has decided to extend His mercy even to the wicked and the ungodly (Matthew 5:45). Pagans go about their lives happily without the troubles that beset the righteous (Psalm 73:4). Consequently, evangelical messages that call on people to be saved to be set free from their troubles in this life usually fall on deaf ears. Why would anyone need to be saved when they're wealthy and successful?
We need to hammer home the message that salvation is God's will (1 Timothy 2:4) and that there is a life after this. Those that mock that reality will find out the cost of their foolishness very painfully.