A client's cheque bounced and they'd even put their guarantee card's number on the back!
So then my bank phoned me with the bad news, but at least in their kindness didn't charge me despite it being quite a lot.
Furious I went off to visit said client and made the bugger cough up with cash. Nothing like a fistful of readies. But I warned him never to darken my smithy again unless presenting me with cash, lest he gets my red hot poker where the sun don't shine.