Customers who come out with a cup of tea to talk, and drink the tea infront of you without offering you any.
and ones who wait till you're finishe dbefore offering you a drink or to come talk to you - got stuck talking to an old lady for half an hour the other day after spending 20 minutes cleaninger her windows - couldnt get away cos she always had something more to say and didnt give us a chance to talk.
I've one like this - yakety yak yak yak yak yak - last time, after 5 mins I said "Ooh! Is that my phone in the van, gotta go - see ya!"
Works and doesn't hurt their feelings.
I don't know if I should add this but I've actually found that about half a dozen of my customers from a certain ethnic background (no races/nationalities mentioned, no pack drill!) are real pains in that they don't pay on time and often try to get lower prices. Maybe they're used to haggling in market places?