I've seen similar ones before but I particularly liked the last sentence...
A shepherd was herding his flock in a remote pasture when suddenly a
brand-new BMW advanced out of the dust cloud towards him.
The driver, a young man in an Armani suit, Gucci shoes, Ray Ban sunglasses
and YSL tie,leaned out the window and asked the shepherd, "If I tell you
exactly how many sheep you have in your flock, will you let me have one?"
The shepherd looked at the man, obviously a yuppie , then looked at his
peacefully-grazing flock and calmly answered, "Sure."
The yuppie parked his car, whipped out his notebook and connected it to a
cell phone, then he surfed to a NASA page on the internet where he called
up a GPS satellite navigation system, scanned the area, and then opened up a
database and an Excel spreadsheet with complex formulas.
He sent an email on his Blackberry and, after a few minutes, received a
response. Finally, he prints out a 150 page report on his hi-tech,
miniaturized printer then turns to the shepherd and says, "You have
exactly 1586 sheep."
"That is correct; take one of the sheep." said the shepherd. He watches
the young man select one of the animals and bundle it into his car.
Then the shepherd says: " If I can tell you exactly what your business is,
will you give me back my sheep?"
"OK, why not." answered the young man.
"Clearly, you are a consultant." said the shepherd.
"That's correct," says the yuppie, "but how did you guess that?"
"No guessing required." answers the shepherd. "You turned up here
although nobody called you. You want to get paid for an answer I already
knew, to a question I never asked, and you don't know the first thing
about my business. ...Now give me back my dog."