Humor can help you get the sales presentation in the first place. It will also help you stay upbeat in the face of rejection, overcome inevitable problems that arise during a presentation, break down sales resistance, and create loyal customers who will buy again. Let me tell you how humor has greatly helped me.
One of the ways professional speakers gain business is to do no fee demo talks in front of potential buyers. I was doing one of these talks for an advertising association in Washington, D.C. After the presentation, a lady came up to me and invited me to call her. She said my information would be perfect for the employees at her government agency. I called three times that week and did not get a return call. I called three times the next week and did not get a return call. I called three times the next week and the week after that. Finally, I got sick of calling so I sent her a funny fax.
She called back within the hour. I went down and got a $3000 contract and another one the following month for $2000. She said my fax really made her laugh in the midst of the constant pressure she was under and that's why she called.
Was my success in this case only because of the humor? No. It was a combination of humor and persistence.