Hmmm, maybe we do need extra classes in how to give literary offence.

Must admit to enjoying a childishly expressed naughty word though...

"You fucking arse-wipe!" is definately more unpleasant, but
"You smellywelly bum-hole!" is more amusing.

Plus the latter has the advantage in a flame-war situation of demonstrating to ones opponent, that you're not particularly distressed by their attacks. It is a virtual way of placig ones thumb on ones nose, wiggling ones fingers and going: >insert silly voice<
"Nurny Nurny Nur Nur!!"

Which I think even you will agree, is possibly the most enraging thing anyone could possibly do, when you're feeling really fucked-off...