There are good clients, and there are Good Clients
I spent a couple of days either side of Flick's wedding installing a whole new set of server-side infrastructure for a client of mine. It involved some long days and some frustration, not least because the old main server was very keen to fall over the moment it was doing anything remotely stressful -- such as, for example, letting me copy stuff off it to put on the new server. That's okay, though -- some jobs are like that.
Today I typed up the invoice for the job. I emailed the PDF off to the client at 12:26.
At 17:16 I had a phone call from them. They've just paid the invoice. That's a shade under five hours, and a new record.