The Universal.

Sometimes something being funny depends on the audience having the same points of reference as you. It's something you have to think about when doing a gig in another part of the country- will they get that in London / Edinburgh. Non of my material is especially regional, I don't talk about Geordies, Chavs or slag off Sunderland, so I'd be alright in most parts of the country. But if I ever get the chance to gig abroad it would get worse. Even if you're playing to the ex-pats who seek out places they can still get steak and chips and John Smiths, you still need to be aware of what they're out of touch with. Whoever won the 'so you think you're funny' got the chance to perform in Canada - and they probably had to rewrite their entire act. And possibly put on a different accent. I don't have an especially strong northern accent- some real 'Geordies' presume I'm a soft southern poof. But some Londoners still presume I'm Scots, so the Canadians would presumably guess I was Norwegian.

But even at home one can slip up by assuming 'everyone knows that!' I had a bit of material sink because I presumed everyone had heard the lyric 'where the corn is as high as an elephant's eye.' I think it's from Oklahoma, I don't know it that well myself, but I just assumed everyone would have heard of it before. Even when the material that flows doesn't depend on knowing this starting point, I think people still need it to go with you. In this case I went on to ask if this system is used to measure all crops in the American West

'I'd like some potatoes please.'
'Our potatoes are as large as the fist of a chimp!'

This didn't work- I think partly because people didn't understand the first step i'd taken to get there. (Though it's pretty weak too.) I'd say it's similar to my recent Star Wars stuff, but as people know Star Wars and Dickens, they understand the first part, are willing to make the jump to the second bit and go with the joke overall.

Anyway, I mention all this because I remembered talking of the practice of nearly pushing someone off a precipice (cliff, castle wall etc.)and saying 'Tell your mother I saved your life!' To my surprise this practice (or at least the use of the accompanying phrase)is not widely used throughout the North. I was waiting for the joyous lagugh which show the audience is thinking 'Oh god, yeah!' and it never came. Beware presuming everyone's childhood was the same as yours.