Isaac Asimov's three laws of robotics:

1. A robot may not injure a human being or, through inaction, allow a human being to come to harm.
2. A robot must obey orders given it by human beings except where such orders would conflict with the First Law.
3. A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

The Midwestern Dad Laws, as modeled by my father, Jeff:

1. A Midwestern Dad may not cause, or through inaction, allow any safety hazards to arise or cause harm to anyone.
2. A Midwestern Dad must obey orders given to him by his wife, except where such orders would conflict with the First Law.
3. A Midwestern Dad must not get ripped off, provided such ripoff does not conflict with the First or Second Law.

Usually it's pretty straightfoward, but conflicts do arise.

Example #1: We're leaving the house to go to a party. My mom (Julie) set up the Christmas lights, but they weren't grounded properly. Even though Julie wanted to get to the party on time, Jeff had to find a grounded extension cord, or take the lights down. Safety first.

Example #2: Jeff at a Christmas tree farm. He knows the trees are overpriced and wants to avoid the scourge of every Midwestern Man: getting ripped off. He buys one anyway, because Julie wants it, and #2 takes precedence over #3.