Cut this tension with a knife

With the turn of each page it gets exponentially harder to trust in the validity of each "fact" Pym tells in his tale. From exaggerated details to discontinued accounts (Grandpa can't see you because its foggy? really? and are poor Pym's parents still wondering where he is?) the tension between fiction and truth becomes pretty strong and obvious. But, I guess my main question is why do people tend to not believe stories when people, especially complete strangers like Pym (though after you know a person well you tend to know if its a tendency of them to lie), tell them? Certain things are hard to believe due to common knowledge; come on Pym, you can't have a water supply that barely lasts four days and make it another 14 days. But who's to say a mutiny, barbaric savages, cannibalism, and drunk sailing could not all happen in a couple years of one person's life? All this to say, don't jump the gun when calling something the truth or a lie (unless its common sense) especially dealing with Poe, as he was a tad eccentric ;-).

Yet Pym even tells us (the audience) in his introduction that everyone is suscepbtible to exaggeration and Pym's exaggeration makes it difficult to percieve the difference between reality and appereance. Were Pym's conditions really as bad as he made them appear? At first he calls his living quarters on the ship a "vacation", which in a couple pages and a little less food turns into an "Incarceration". Another example is his hideout in the island's hill which was first described as a "penthouse" and later called a "cell". Pym's exaggeration makes it hard to believe and discern reality and validity to his facts, which is why it's probably hard to believe someone's story because once one fact is exaggerated, it gets harder to listen to each one told after that.