I say fiddlesticks. It's the result of having spent too long going to religous school where you could get a detention for saying butt. It's also handy to have substitutes for swear words when a good many of your customers are older than your grandmother. (Not that I'd swear at the ladies. I'm afraid I have been known to get my fingers caught in drawers, however. :) )

From my family, I mostly heard odd random phrases in Swedish and Latin, and such colourful phrases as "sucking canal water". I rather like that one. :)