What is this?
Humor is levity, the ability to express or recognize sayings or situations which we find funny, the ability to interact without strict or serious protocol.
Why is this important?
When humor is a part of your approach to persuading others and negotating with them (within appropriate limits), it is very effective in lowering resistance in others. The key to using humor is to stay within yourself, and to stay within socially acceptable bounds in your use of humor. It will not help you to approach persuading others with humor to the extent that it distracts from what you are there to accomplish.
People who approach persuasive situations or negotiations without some degree of humor are often seen as stiff, unfriendly, or even uninteresting and unlikable people. This increases the likelihood of resistance to your proposals, assertions and suggestions. The idea is not to become a comic, but rather to have a genuine, easy, friendly, sense of humor that you can use to make other people's experience with you more pleasant and rewarding...and the process a little more fun.