Offered without comment as none is needed:
The brain reacts in exactly the same way when a talk goes wrong.
You see an error on the screen that you’ve never seen before. Your demo has broken on a line that you don’t remember writing. For some reason, the error message is in Greek.
Your forehead tingles as blood floods the capillaries, flushing your face in seconds and turning it into an I’M A F***CKING IDIOT beacon for everybody to see. Sweat creeps out of glands in places you didn’t know you had ‘em, you suddenly become acutely aware of your own body odor, and then your eyes resolve the blurry thing that’s just beyond the monitor – yes, the audience – that’s what it is, and it’s staring at you, shocked, and sending you a telepathic message which goes something like “Yes, Rory, your I’M A F***CKING IDIOT beacon is working properly. We can all see you up there, being acutely aware of your own body odor. Please resolve this soon or we will eat you.”
More at http://neopoleon.com/blog/posts/17449.aspx