Nightmare Fuel / The Purge Universe

• The entire concept of the Purge. Imagine you lived in a country where every year people are given carte blanche to kill, loot, pillage, and rape to their heart's content. Sure, if you've got the cash you could pay for various means to protect yourself from the yearly slaughterhouse, but not everyone does and some sellers purposely build in flaws to their security systems so you'll get murdered while thinking you were safe the entire time. The government is in on it, there are no emergency services allowed during the Purge, so you have no one but yourself and maybe friends and family to help you out (provided they aren't out for your blood). And all of this is perfectly legal and has caused a great economic boon for your nation which gives absolutely no incentive for anything to change. Sweet dreams, folks.
• The idea that conventional people of American society are all too willing to randomly pillage and kill just because there's no legal repercussions. To fall for it you'd have to believe almost everybody in the country is a sociopath. What makes it worse is that you never know who is going to participate in the Purge. It could be a friend, family member, lover, or a random person you saw on the street and the next victim could be you.
• The chipper tone of the New Founding Fathers of America website as it recommends Purge tourism destinations (travel expenses for the Purge are now tax deductible and Portland's human remains powered BioMass Transit is quite the attraction), the best cocktails for your Purge party, and this year's must-have Purge gadgets.
• While the Emergency Broadcast announcing the Purge's commencement is cited as an In-Universe Hell Is That Noise, what really takes it home is the ungodly siren at the end announcing the suspension of law and order for the night. Have a listen, why don't ya, and good luck getting to sleep tonight.