Reminds me of a mate of mine who decided to check his car over before setting off on a long journey. The tyre, water,oil, washer fluid etc all looked OK, so he called his wife out to help him check the lights while he sat in the car and turned them on and off.
First he turned the headlamps on.
"Are they working?" he asked.
"Yes, they are," she replied.
Then he pressed the brake pedal.
"Are the brake lights working?"
"Yes they are."
Then he pushed the indicator stalk down.
"Are the left indicators working?"
"Yes they are, no they're not, yes they are...."