OK, after reading all this I'll throw my favorite in here:
A man is driving cross-country and notices an apple stand on the side of the road with a big sign that reads "Apples $1". Being curious he approached the stand and asks "Why are your apples 1 dollar?". The vendor replies "These are the best damn apples around, they taste like peanut butter and jelly". "Really? replies the man and proceeds to purchase an apple. He takes a bite and says "Hmm, creamy peanut butter, but where's the jelly?". The vendor says "Turn it over". The man turns the apple over and takes another bite, "Mmmm, delicious grape jelly".
On his next road trip he sees the same apple stand but this time it reads "Apples $2". So again he asks, "Why are your apples 2 dollars?". The vendor replies "These apples are better than before, they taste like ham and cheese". "Really? replies the man and proceeds to purchase an apple. He takes a bite and says "Hmm, delicious ham, but I don't taste the cheese?". The vendor says "Turn it over". The man turns the apple over and takes another bite, "Mmmm, tasty cheese."
Finally on his final road trip he sees the same vendor again but now the sign reads "Apples $5". Not being able to imagine why an apple would cost so much he asked, "Why are your apples 5 dollars?" The vendor replies, "These are the best apples yet, they taste like p*ssy". The man quickly whips out 5 dollars, hands it to the vendor and takes a big bite of an apple. He heaves over and spits it out, "This tasts like sh*t". The vendor replies, "Turn it over".