It's not always a case of demonstrating our boredom through the ways we shift in our seats. Sometimes we may even sit on the edge of them. Some presentations are truly fascinating and cause us to nod our heads up and down in agreement with what's being said, or to smile with the recognition that we're being enlightened.

I frequently instruct my audiences to give me feedback by either nodding or shaking their heads so that I'll know if what I'm trying to express is getting through. Though I can't say that I enjoy being interrupted in the middle of a presentation, I greatly prefer that to being met with blank stares. A good audience is a feisty audience.