Villains.
Just the thought elicits visions of maniacal 
laughter, devilish plots, bumbling sidekicks, and plans to take over / dominate / destroy the Earth. We root for their failure, cringe at their dastardly deeds, and weep at the havoc they wreak.
But to a superhero, these evildoers are as important as ying is to yang. Without them, there would be no dark to offset the light side of the force, no one from whom to rescue Lois Lane, and no one to threaten Gotham City. If the Jedi had been successful at stopping the Emperor, the Empire would have never come to fruition, and OB1 and Anakin would have found themselves unemployable.
Mystery Thriller Week 