If you are offended by potty language, I'll have to ask you to leave. Do not pass go. Do not collect $200.
FFS means "for fuck's sake." I work in a total diversified, politically correct, tolerant, harassment-free environment, which came about after a couple of major lawsuits against the Mother Ship.
The couple of us rebels still have our ways of being politically incorrect, and FFS is one of them. It drives many people nuts when we say it, because they don't know what it means. Another of our gems is Canadians. This is what we use when we want to call someone an idiot.
*Disclaimer* Canadians are not idiots, and I am rather fond of most of the Canadians I know. The code word for idiots came about after one particular frustrating day (I work in IT so I deal with some real winners), and involved a lot of tequila.
We were sitting around trying to come up with a word to mean idiots, and this guy in the bar yelled "Damn Canadians!!!" at the TV (hockey was on I think? It's kinda a blur), so Canadians was the logical choice. It was like an act of God I tell ya.