Harry Potter and the Goblet of Fire Theme of Fear

Fear generally makes people stupid in the Harry Potter novels. A great example of this is Cornelius Fudge, the Minister of Magic. In Goblet of Fire, he's so committed to his denial of Voldemort's rise that he refuses point blank to believe Harry's eyewitness testimony. What's more, he rejects all of Dumbledore's excellent advice about not letting the Dementors maintain control of Azkaban Prison (this right after watching a Dementor eat Barty Crouch, Jr.'s soul before they can get an official statement from the guy). The Death Eaters thrive on fear because it causes social division and confusion among their victims. It also makes people like Cornelius Fudge easier for the bad guys to control.

1. Why do the Death Eaters decide to play their nasty little prank at the Quidditch World Cup, before they even know that Voldemort is trying to rise again?
2. How does Harry cope with fear? When does he feel most afraid? How is he able to overcome his fears? Do his strategies change over the course of Goblet of Fire? If so, how?
3. We all know that Voldemort uses fear to control his followers (especially pathetic Wormtail). Are there other characters in Goblet of Fire who use other people's fear for personal gain? If so, who are they? Whose fears do they take advantage of, and why?