A friend and I stayed at a Chicago hotel while attending a convention. Since we weren't used to the big city, we were overly concerned about security.

The first night we placed a chair against the door and stacked our luggage on it. To complete the barricade, we put the trash can on top. If an intruder tried to break in, we'd be sure to hear him.

Around 1 a.m. there was a knock on the door.

"Who is it?" my friend asked nervously.

"Honey," a woman on the other side yelled, "you left your key in the door."