I get that "brain sizzle" look from guys who ask about my gyro when I tell them how the rotorblades are not powered in flight like a helicopter. I explain that it is just like how a maple seed spins to the ground, or how the common windmills spin when the wind is blowing.
The best reaction of shock I've seen is when airplane pilots ask at what speed we rotate (ie: command the gyroplane to lift off, like they do by pulling back on their yoke to change the wing's angle of attack, and separate from the ground into flight).
I tell them that we don't command the gyroplane to lift off. We maintain the same stick position while smoothly adding power, and wait until it lifts off by itself! One pilot then started blinking his eyes rapidly, like the proverbial robot that couldn't comprehend a command that is beyond it's ability to process the information!
I also explain that the rotorblades self-rotate (that's why they are called auto-gyros), so when they're ready to fly, they give us a clue to then add throttle smoothly.