What's your favorite swear word/insult?

[Cyberman]

As for British swears/insults. I have to go with git. I know it's not a swear, but it's so versatile.

It is a swearword actually, though rather low on the food chain. As with almost all epithets, what matters isn't so much the word itself but the invective behind it. I could greet a friend with “hey there, you old git; how you doing?“ - which is a world apart from “get away from me you stupid git.“

Incidentally, on the subject of how swearwords lose their sting over time: there's the word “berk“, meaning an idiot or buffoon (or a Dubya), which is so harmless and somewhat quaint now that it was even used as the name of a much-loved character on a childrens' claymation series The Trapdoor, voiced by the late great Willie Rushton. Consider, however, that the word is derived from Berkshire Hunt, cockney rhyming slang for... well, something that rhymes with Berkshire Hunt, and it's a wonder they got away with it.

Then again, things are always slipping past the censors. Kenny Everett had his diva character Cupid Stunt, the Goons were masters of phrases such as Hampton Wick and Pink Oboe back in the fifties, and even clean-cut George Formby had a filthy mouth a decade earlier.