(Well I don't know if they are the scariest but they certainly rank high up there.)
"GOD GAVE THEM OVER." This not a passive phrase; it is active. It is not something that happens as a result of someone's actions.
Unseemly perverted sexual deviancy is not just another among a plethora of generic sins that God will judge; It is unique in that He deliberately and purposefully delivers the sinner into the grip of his own cherished sin. Homosexuality (and other forms of sexual perversion) is a direct judgment from God to men who refuse to acknowledge and honor Him. It is a deliberate judgment for deliberate unbelief. And if you think you can stand before Him someday and convince Him that you didn't know, think again. He has sufficiently revealed Himself to and within every man so they are without excuse.
Read this carefully and be warned:
"The wrath of God is revealed from heaven against all ungodliness and unrighteousness of people who suppress the truth by their unrighteousness, because what can be known about God is plain to them, because God has made it plain to them. For since the creation of the world His invisible attributes—His eternal power and divine nature—have been clearly seen, because they are understood through what has been made.
"So people are without excuse. For although they knew God, they did not glorify Him as God or give Him thanks, but they became futile in their thoughts and their senseless hearts were darkened. Although they claimed to be wise, they became fools and exchanged the glory of the immortal God for an image resembling mortal human beings or birds or four-footed animals or reptiles.
"Therefore GOD GAVE THEM OVER in the desires of their hearts to impurity, to dishonor their bodies among themselves. They exchanged the truth of God for a lie and worshiped and served the creation rather than the Creator, who is blessed forever! Amen.
"For this reason GOD GAVE THEM OVER to dishonorable passions. For their women exchanged the natural sexual relations for unnatural ones, and likewise the men also abandoned natural relations with women and were inflamed in their passions for one another. Men committed shameless acts with men and received in themselves the due penalty for their error.
"And just as they did not see fit to acknowledge God, GOD GAVE THEM OVER to a depraved mind, to do what should not be done. They are filled with every kind of unrighteousness, wickedness, covetousness, malice. They are rife with envy, murder, strife, deceit, hostility. They are gossips, slanderers, haters of God, insolent, arrogant, boastful, contrivers of all sorts of evil, disobedient to parents, senseless, covenant-breakers, heartless, ruthless. Although they fully know God’s righteous decree that those who practice such things deserve to die, they not only do them but also approve of those who practice them."
Romans 1:18-32 New English Translation