Stupidity: When Christine is told that to remove the curse, all she had to do was give an envelope with the button inside to somebody else and that individual would go to hell. She decides to go to the cemetery where Ganush is buried and places an envelope into her mouth. Had Christine actually bothered to check inside the envelope first to see if the button was inside, she would never have gone to hell.
Stupidity: In the opening scene, when Jason lunges at Whitney, the screen cuts to the title card with his machete swinging 12-6 just inches from her skull. This makes it hard to believe he had a change of heart and pulled his windup before splitting her head in half.