Years ago I was an employee of a local firm that does a lot of research and development. I shared a lab with a fella, and we had a section set aside for tools and drill press, etc.
There was this fella that would come in whistling a tune, as he would go over and use the tools.
He came in on a regular basis, and I knew that he was always whistling... so I turned to my lab partner and said "Watch this." I started to whistle some Beetles tune. Well, the 'whistler' picked up on the tune, and left the lab whistling it.
A little later, he comes back into the lab to use the tools and he is still whistling the same tune. (We're talking not just one refrain... but the ENTIRE song!)
This went on for a bit, and my lab partner turns to me and says quietly, "Will you PULLLEEEEEASE change the tune?", to which I started whistling a new tune... which the 'whistler' picked up on, and left the lab, whistling the new tune.
My lab partner and I looked at each other... and burst out laughing. The 'whistler' never knew that I was doing this to him... he just started whistling the tunes that got stuck in his head, I suppose.
Regards,
Jim TX