Flying Monkeys

Today I'm feeling like Dorthy in The Wizard of Oz when the Wicked Witch sent her army of evil flying monkeys to attack Dorthy and Toto.  I have countless satisfied customers that love my work and refer me to their friends. Then I've had about three customers that I can not please and seem to reemerge continuously. They are always successful at dampening my mood. Since they seem to swoop down on me out of no where, I refer them as flying monkeys. I'm sure that every industry has their own description of a disgruntle customer, here is mine:
-Flying monkeys don't know what they want. They give me a vague description to work with.  They know what they don't want and are very comfortable requesting a vast series of never-ending adjustments.
-Flying monkeys expect work done on the fly. This disrupts all my other orders and crushes my personal life. They also gets p.o.ed if the extra shipping is included in the invoice.
-Flying monkeys always try to weasel out of payment: "I thought this was a promotion." "I'll pay you in two weeks."
-Flying monkeys typically have their personal lives in shambles and never pass up an opportunity to campaign for the sympathy vote.
-Flying monkeys always attempt to befriend and later pull the friend card.
If this sounds like the customer from hell, yes indeed it is. I've had three of these and they never seem to go away completely. Today all three contacted me! Sorry, I board my plane for Belize in two hours, go fly somewhere else and find some other dedicated person to pick on.