Cut the jokes
Just possibly this tactic will draw a stony smile. Since you're alert, you'll see it coming - and will change your tactics accordingly. As with all trick questions, the reflex is to turn a negative into a positive - otherwise known as inventing a problem where there isn't one.
For example, here is a "serious" answer to What is your biggest weakness? You're inventive, you'll easily think of others.
Answer: I'm always slow to start a project, studying the background takes time when you need to be thorough.
