In the dead of summer a hot, dry fly was resting on a leaf beside a lake and said to no one in particular, "Gosh... if I go down three
inches...I will feel the mist from the water and I will be refreshed."

There was a fish in the water thinking, "Gosh... if that fly goes down
three inches, I can eat him."

There was a bear on the shore thinking,"Gosh...if that fly goes down three inches... that fish will jump for the fly... and I will eat him."

It also happened that a hunter was farther up the bank of the lake
preparing to eat a cheese sandwich. "Gosh," he thought, "if that fly goes down three inches...and that fish leaps for it... that bear will expose himself
and grab for the fish. I'll shoot the bear and have a proper lunch."

You probably think this is enough activity for one bank of a lake, but I can tell you there was more.

A mouse by the hunter's foot was thinking, "Gosh...if that fly goes down three inches... and that fish jumps for that fly..and that bear grabs for that
fish...the dumb hunter will shoot the bear and drop his cheese
sandwich, and I'll eat the sandwich."

A cat lurking in the bushes took in this scene and thought, as was
fashionable to do on the banks of this particular lake around lunch time, "gosh...if that fly goes down three inches...and that fish jumps for that fly...
and that bear grabs for that fish.. and that hunter shoots that
bear...and that mouse makes off with the cheese sandwich.... then I can
have mouse for lunch."

The poor fly is finally so hot and so dry that he heads down the few inches for the cooling mist of the water.

*AND*

The fish swallows the fly...
The bear grabs the fish...
The hunter shoots the bear...
The mouse grabs the cheese sandwich...
The cat jumps for the mouse...
The mouse ducks...
The cat falls into the water and drowns.

The moral of the story is:
Whenever a fly goes down three inches...some pussy
is in danger.