What do you do when you're having one of those days from management hell? The type of days when everything goes wrong, when you fumble or stumble, when everything you do or you say is just the wrong thing to do or to say? When everything you do or say proves conclusively to everyone around you that you're not the person you'd like them to think they are.

Try laughter. Try making a joke out of it, using self-deprecating humor. It shows confidence. It shows that you're amazed things went wrong. It makes what could be a problem fun for the people you're dealing with.

Humor persuades. In one study of humor in negotiation, "buyers" who made their final offer with a smile and a quip, "Well, my final offer is x dollars and I'll throw in my pet frog," were able to make the buy at a lower price. Sellers who laughed out loud were even more likely to grant concessions than those who didn't. Imagine if the joke had actually been funny.

You can use humor to get attention, build rapport, break down resistance, make a point more memorable, and get people to listen and to enjoy listening. The old dictum is true: when you're funny you don't have to yell. Always make sure the humor is appropriate, of course. "If you would rule the world quietly," Emerson said, "you must keep it amused." You can rule your business the same way

In The Light Touch, humor expert Malcolm Kushner tells a story of Adelle Roberts, a police officer called to the scene of a domestic disturbance. As she approached the house, a TV came flying out a window. She knocked loudly to be heard over the yelling.