On the second day, God created the dog. God said to the dog, "What you are supposed to do is to sit all day by the door of your house. Any people that come in, you will have to bark at them! I'll give a you lifespan of 20 years."
The dog objected, "What? All day long to sit by the door? No way! I give you back 10 years of my life!" So God agreed.