...are, apparently, "Fuck" and "Shit".
As we all, if we're lucky, fuck and, unless we're particularly unlucky, shit, they're not discriminatory and, therefor, less offensive.
Unless you call some a lazy shit or a lazy fuck? Or whatever. ???
Arse is a pre-watershed word for the BBC now too.
And the most offensive?
I guess it depends on who's being sworn at/to...