Originally Posted by Summer!!

I agree with all what you said, especially about bullshitting answers. They are some really good pointers. And I like the joke.
However, I gotta say that cracking a joke is not a good thing sometimes; it really depends on what kind of presentation. A friend of mine was presenting (it was supposed to be semi - formal) to class about some network security protocol, he made a joke about some celebrity who had their cell phone hacked into as a way to explain the purpose of the protocol. Everyone laughed, but the examiner didn't think it was appropriate, and ended up down grading him.
As for examiners not wanting you to fail, well one of my teachers used to say that some examiners ask questions with the intention to rattle the presenter, make them look bad, and find the excuse to fail them. It is a strategy to weed out the weak ones.