My worst off the cuff pun

[suityou01]

In my days pre-IT, when I was a proper electronics engineer, I went to many of these annual electronics exhibitions / trade shows in that there London.

At one, a guy from a well known hardware manufacturer came over and said:

"Escuse me, do you use switches?"

To which I replied "On and off".

DP that has made my evening, thank you.