Last Updated Apr 16, 2009 8:30 AM EDT
By telling your audience that you prepared for the talk at the last minute -- or not at all.
As Tammy Erickson blogs on Harvard Business Publishing:
At a minimum, this demonstrates a lack of respect for the importance of the event or other participants. In most cases, you also decrease the authority of your conclusions.(Erickson has several other good tips on when it's better to keep your mouth shut.)
Have you had this experience as a presenter, or misread the room to the extent that you lost your audience in the first 60 seconds? How did you recover? What did you learn from that experience?