In the LOTR book trilogy, there is a good wizard named Saruman who is seduced by evil.   While Saruman's magic power isn't well defined. It is illustrated that one of his abilities is influencing others into believing everything he says is true. Whatever Saruman says, is what people believe.   Late in the story, Saruman's tower is attacked by treeborn Ents and the area becomes flooded with water. Saruman's situation is desperate.   In his desperation, Saruman unwisely abuses his power and overexerts himself, shattering his own magic.    This has always been interesting to me. Saruman was never directly defeated in combat or war. Instead his story is that of a wizard who apparently defeats themselves.   Is this something that actually happens in the real world? Or is it merely fiction?    How did JRR Tolkien come by this plot twist.   Long story short, people say I waste my time paying attention to fictional stories. Maybe they're right. 
Or perhaps there is something that might be learned at times?