Best signature I have seen in a long time..........."Of course you want it done today, if you had wanted it done tomorrow, you would have waited until then to call me."
On occasion, when a customer is being a pest about getting the job done NOW, I offer them the costumers phone # that I'm already "scheduled" to do NOW, so they can explain to them that I won't be able to be there because I'll be doing yours instead. They seem to back off then.