One day at work, I put a small indicator light on my hard hat.
Ran the wire down the back, down the neck, into the shirt, down the arm, and had a pushbutton switch in my palm.
Walked near one of the bosses at work.
As I got closer, I made the light go on/off, faster and faster.
When he asked me what was up with the light on my hat, I said...
Oh is that on?
It must be broken.
It's an idiot detector, and it wasn't on earlier.