Me: *pays with a ten pound note*
Server (handing me six pound coins and some shrapnel): Sorry, no fivers.
Me: No worries. Just a sec, this one's a fake. And this one... oh, and this one too. Do you have any real money?
He did, at least, exchange them without fuss, but I bet they went straight back in the till for the next poor sod who is in too much of a hurry to check their change. After all, he'll just get in a heap of trouble at the end of his shift if he's short by a few pounds.
If I have to put up with much more of this, I'm going to start paying for everything with my own personal currency, which will consist of notes saying "I promise to moon the bearer on demand". This, you understand, is a more meaningful promise than you get from the Bank of England.
And despite all this, I still seem to have another two of these bastard things in my wallet. To whoever's making them: if I find out who you are, I intend to cram them into all of your available orifices until you die of lead poisoning.