On the first day, God created the cow. He said, "You must work in the field all day under the sun. I give you a life span of 50 years."
The cow objected, "Such a tough life for 50 years? I'll take 20 and give back 30." God agreed.
On the second day, God created the dog. "Sit by the door all day and bark at visitors. I give you 20 years."
The dog objected, "All day by the door? No! I'll take 10 and give back 10." God agreed.
On the third day, God created the monkey. "You must entertain people, make them laugh with tricks. I give you 20 years."
The monkey objected, "Make faces and tricks? Ten years is enough; I'll give back the other 10." God agreed.
On the fourth day, God created man. "Your job is to sleep, eat, play, and enjoy life. I give you 20 years."
The man objected, "Only 20 years of such a good life? No deal! Since the cow, dog, and monkey gave back 30, 10, and 10 years, I'll take them. That makes 70 years for me!" God agreed.
AND THAT'S WHY
For our first 20 years, we eat, sleep, play, and enjoy life.
For the next 30 years, we work hard all day to support our family.
For the next 10 years, we entertain our grandchildren with funny faces and tricks.
For the last 10 years, we stay home, sit by the door, and bark at people!