9. Mind Control
For all the good Superman has done, there are some like Lex Luthor who fear the Big Blue will turn against humanity. Of course, Supes has reassured humanity countless times, emphasising that he would never use his power for evil since he stands for truth, justice and the American Way.
Despite Superman's intentions, Lex has a point. Even though the Boy Scout superhero can benchpress a planet and crush a diamond with his eyelid, his mind can be corrupted. Poison Ivy used her pheromone control to brainwash Superman, forcing him to attack Batman. Maxwell Lord manipulated his mind so Superman thought he was fighting Doomsday and Brainiac when he actually attacking his friends.
One of the most terrifying moments in Superman's life was when his body was possessed by Eclipso - the embodiment of God's Wrath.
Intending to use the Man of Tomorro's body to cause untold levels of destruction, Shazam intervened and tried to rip Eclipso from his friend's body. Unable to defeat the ancient demon, Shazam's mentor summoned the embodiment of God's Vengeance, The Spectre, who had Eclipso imprisoned. If it wasn't for The Spectre's appearance, Super-Eclipso could've theoretically levelled the planet in a matter of minutes.