It was during that production of Alice's Adventures in Wonderland (I'm a stickler for the inclusion of "Adventures"; if Lewis had wanted to call it Alice in Wonderland, he would've; blame Disney), that I formulated a key criterion for personal couth. The conclusion of our outdoor play happened after the sun had set, necessitating a quick change for me, from the Executioner to Duckworth, behind a tree in the twilight. And so I had my definition: "A gentleman is someone who can tie a proper bow-tie in the dark."
(Did you know the Queen is reported to hate clip-ons?)
But I was eclipsed by a good alternative, which surfaced during a recent radio interview with Steve Martin, about his new (and hugely enjoyable) bluegrass album: "A gentleman is someone who knows how to play the banjo -- but doesn't."
Okay, it's funnier than mine, but it loses points because I've heard it before, applied to the piano-accordion.