Cassandra Truth examples on South Park.
- In "The Day Before the Day After Tomorrow", Stan finally decides to come clean and tell the town that he destroyed a beaver dam and caused a massive flood in a neighboring city. The adults of the town, being complete idiots, misinterpret this as him saying that everyone in South Park is to blame for the destruction of the dam. The episode ends with everybody in the town saying, "I broke the dam", and Stan's yelled confession being ignored completely.
- In "Time to Get Cereal", Stan and the others tell the police that they weren't responsible for the killings in South Park and ManBearPig is on the loose, but they refuse to believe them and have them arrested for the killings.
- In "Cartman's Incredible Gift", Stan and Kyle know who the serial killer in this episode is, but the police refuse to believe the two of them and only listen to fake psychic Cartman, who is just using them to arrest anybody he has a grudge against. Kyle realizes that the only way the idiot police will listen to him is if they think he's a psychic as well; he repeats the same accident that gave Cartman his "powers" himself. Even then, the police are still skeptical of Kyle since he isn't as "professional" as Cartman.
- "Le Petit Tourette" has Cartman faking Tourettes Syndrome in order to get away with cursing at everyone, especially towards Kyle. Kyle knows Cartman is lying yet again and tries to tell the leader of the Tourettes Syndrome support group that Cartman is faking it, but the guy refuses to believe Kyle and thinks he is just being intolerant.
- In "The Death Camp of Tolerance", Stan and the others try to report Mr. Garrison's inappropriate behavior to the adults. Of course, the adults stupidly misinterpret this as them being homophobic and have them all sent to a Schindler's List-esque concentration camp as punishment. Chef is the only one who understands them, but he also gets labeled as a homophobe himself and gets sentenced to counseling.
- In "AWESOM-O", Cartman finally confesses to not being a robot to the military and scientists who try to experiment on him, but they all believe he is simply in denial about being a robot. It's not until he lets out a fart that they start to realize he's actually a human.
- In "The Biggest Douche in the Universe", Stan makes his own rival show to John Edward's "Crossing Over". He begins every episode by saying that his (and Edward's) statements and "communications" were simply tricks and hoaxes. No one believes him.
- In "Spookyfish", when Stan tells his mom that his fish is killing people, she doesn't believe him.
- In "Mystery of the Urinal Deuce", the reason why the government runs all the conspiracy theory websites for 9/11 is that 1/4 of Americans are retarded and refuse to believe them when they tell them what actually happened.
- In season 20, nobody (understandably) believes Cartman when he denies being infamous SkankHunt42, an anonymous, resilient troll who's causing a massive rift between the boys and the girls in school due to his cyberbullying. It gets to the point that the boys, sick of being the scapegoats, thanks to one bad apple, break all of Cartman's electronic devices just so he can't go online and harass anybody. Shockingly, for once, Cartman was 100% telling the truth; he's in fact completely innocent of SkankHunt42's crusade, as the identity of the troll is revealed to be Gerald, Kyle's dad. Kyle later on even walks up to Cartman and wholeheartedly apologizes to him for their mishap.
