Your health teacher: HERPIES IS DANGEROUS AND IS VERY SEVERE!!! 

Reality: 90% of the current world population have herpies.
They're not a dangerous or life threatening disease.
Think of herpies like acne, or a rash. We treat it like the chicken pocks when it's really one of the post common sexually transmitted diseases out there...
Just look it up, it's pretty common.
((Credit: Adam ruins everything, Adam Connover.))

COMMERCIALS: (CEREAL NAME) IS PART OF A BALANCED BREAKFAST!!!

Reality: Are you kidding me? First off, who eats that much for breakfast. Am I the only one noticing that they eat WAY too much food in breakfast commercials???
And secondly, who sits around the table for a full on family breakfast anymore? Not that there's anything wrong with that...

And thirdly, wasn't cereal invented by the guy who said we should chop parts out dicks off? (They also said we should put some sort of acid around our vaginas so we wouldn't mastrabate/have sex)