Back in the old folk club days that some of us get nostalgic about, groaning yet excellent jokes tended to be delivered perfectly by the late lamented Tony Capstick. I can still picture him now, with his one liners whilst tuning his guitar;

What's the difference between light and hard? You can go to sleep with the light on.

What have Lobster Thermidor and a blow job got in common? You don't get either in our bloody house.