On the day God created a cow, God said: "You must go to the field and stay
with the farmer all day long, toil pulling the plow and suffer under the
sun, have calves, feed them and also give milk to support the farmer. I
will give you a life span of sixty years."  And the cow said, "That's a
kind of a tough life you want me to do all that for sixty years. Let me
have twenty years and I'll give you back the other forty." And God agreed.

On the day God created the dog, God said: "Sit all day by the door of your
house and bark at anyone who comes in or walks past. I will give you a life
span of twenty years."
The dog said, "That's too long to be barking. Give me ten years and I'll
give back the other ten." So God agreed (sigh).

On the day God created the monkey, God said, "Entertain people, do monkey
tricks, make them laugh. I'll give you a twenty year life span." The monkey
said, "How boring, monkey tricks for twenty years? I don't think so. I'll
take ten years and I'll give you back ten." And God agreed again.

On the last day God created man. God said," Eat, sleep, play, enjoy life.
Do nothing, just enjoy and enjoy. I'll give you twenty
years."  And the Man said, "Why? Only twenty years? It's not enough. Tell
you what, I'll take the twenty years, plus the forty cow gave back, plus
the ten dog gave back and the ten monkey gave back. That makes eighty,
okay?" "Okay," said God agreeing again.

And these events explain why for the first twenty years we eat, sleep,
play, enjoy, and do nothing. For the next forty years we
toil in the sun to support our family. For the next ten years we do monkey
tricks to entertain our grandchildren; and for the last ten years we sit in
front of the house and bark at everybody.