A husband and wife were having a quarrel over the breakfast table. The quarrel remained unresolved when it was time to leave for work.

The wife, having trouble with the zipper on her dress, asked for assistance. In a huff, the husband freed the zipper and then angrily ran it up and down rapidly several times.

That afternoon, when the wife returned from work, she saw him lying on his back with his hands and head under the car working on it. Still mad about what he had done that morning, she went over, grasped his zipper and yanked it up and down several times.

Stomping into the house, she found her husband drinking a cup of coffee at the kitchen table.

In great embarrassment, she explained to him what she had done.

He rushed outside to find his neighbor, who had offered to fix his car, out cold. When the wife had grasped his zipper, he had reflexively tried to sit up and had knocked himself out on the frame of the car.