I don't generally like swearing. People tend to use the f-word, and various other swear words at the drop of hat, sometimes literally. I can count the number of times I have used "the usual" swear words on two hands with fingers left over.
But even though I dislike swearing, that doesn't mean that when something terrible happens, or someone is really really wrong, I don't want (or have) words to use.
Some words came from (the Harry Potter) fandom. Words such as T00b, or my favourite, ass-hat. Calling someone an ass-hat, or telling them they are t00berific can be satisfying, although since I started at my current job more than a year ago, another word has been introduced to me.
I learned it from my co-worker K, who when really frustrated with something or someone, and at work will say "You PEANUT!". Peanut, is an excellent thing to shout at someone. It's a non-offensive word that never the less conveys your feelings about them at that particular moment.
Although I still wouldn't use it on customers whilst in hearing distance :P Not even if they well and truly deserved it.
And when I am really annoyed, and want to vent steam, I have a phrase that my mother uses :D I won't try to write it, as I'll spell it wrong. But it is really really effective. <3