This fellow is looking to buy a saw to cut down some trees in
his back yard. He goes to a chain saw shop and asks about
various chain saws.

The dealer tells him, "Look, I have a lot of models, but why
don't you save yourself a lot of time and aggravation and get
the top-of-the-line model. This chain saw will cut a hundred
cords of wood for you in one day."

So, the man takes the chain saw home and begins working on the
trees. After cutting for several hours and only cutting two
cords, he decides to quit. He thinks there is something wrong
with the chain saw. "How can I cut for hours and only cut two
cords?" the man asks himself. "I will begin first thing in the
morning and cut all day," the man tells himself.

So, the next morning the man gets up at 4 am in the morning and
cuts and cuts, and cuts till nightfall, and still he only
manages to cut five cords.

The man is convinced this is a bad saw. "The dealer told me it
would cut one hundred cords of wood in a day, no problem.
I will take this saw back to the dealer," the man says to
himself.

The very next day the man brings the saw back to the dealer and
explains the problem. The dealer, baffled by the man's claim,
removes the chain saw from the case. The dealer says, "Hmm, it
looks fine."

Then the dealer starts the chain saw, to which the man responds,
"What's that noise?