I bet one reason there are Devil's Advocates on this site is that so many people believe anything their high-school teacher tells them.
That's because what their high school teachers tell them is believable.
Sky mirrors are not believable. Weird huh?
Is quantum physics and GR believable? How about Dark Energy and reverse time symmetry (CPT violations will blow your mind)? How about the delay choice quantum eraser?
http://en.wikipedia.org/wiki/Delayed_choice_quantum_eraserThere are a lot of generally unbelievable things out there in modern physics.
As far as high school teachers, they are a great bunch, but sometimes they get it wrong like anyone else. That is why its important to sometimes critically examine what one has held to be true. This is especially important if the idea becomes so self evident to oneself that it is assumed without thought in any situation.