I hope not being too off-topic, but there are some curiosities about the way we brazilians use curse words that will add some information to this discussion.
First of all, I realize there's a very basic diference between the way we Portuguese speakers use bad-words from the way you English Speakers do. Our way of offending other people is ever, or almost ever, from a sexual poit of view, while in English (and in german too, I guess) there's a lot of reference to feces and excrements.
One example could be a sentence that I found quite often in movies : "Hey, kiss my a** !". I suppose the point in this statement is a kind of humiliation for the person who is to perform the kiss, in a part of the body so close to the feces or excrements. But here in Brazil the translators that work in the subtitles for the movies seem unconfortable with this, becouse for us, and our cultural sexual point of view, it sounds like a homosexual invitation, not as an offense at all.
Another example is to call somebody a "brown nose", here we'd call this kind of person a "puxa-saco" or a "balls-puller", from the most sexual point of view possible.
The only reference to excrements I can remember happens when something goes very wrong, like to hit a finger with a hammer, and most of us would shout "merda!", very like the french, that is "sh*t!". But we could hear also a lot of "Puta que pariu!", that is a kind of "whore that has gave birth to!" (gave birth to the hammer, in this case) or "que buceta!", (what a vagina!).
The teenagers from here use to curse all the time too, and the most commom is "a fuder!", (good to f**k), "do caralho!" or "bom pra cacete!" (from the pennis, or good to the pennis), all used as an adjective meaning "very good, or cool". They use a lot of "vai te fuder!" too, that is very like your "Go f**k yourself!". Also there's the "Aqui oh!"(here!), that is complemented by a gesture pointing to your own genitals, or the big finger of the hand, sugesting an invitation to the offended to perform felation with the ofender.
Living in a place with a lot of Italian imigration, we used to hear the older people use religious words and sentences to curse when they were really angry. It was common to hear somebody shouting "Puta Madonna!"(Whore Virgen Mary!), "Porco Dio!"(Pig God!), and some less profano like "Sacramento!"(Sacrament), "Ostia!"(Host, holy bread !). These statements were ever very, very loud and pronunced, in a good Italian fashion. Today even the younger use this way to curse, but in a quite "funny" way, just to mimic the tradition of olders.
This account just to the very south of Brazil, and I should say that we are one of the states that use these bad word the less. Even teens know they are being wrong when saying that close to the olders, or women, and most of them respect, or at least be quite embarrassed. More to the North, like Rio de Janeiro, the commom people is very offensive, IMO, and the streets and schools are much more "dirty" from the bad-speaking point o view.
While writing these lines, I realized that all these words don't have a real meaning, and the proof is that when making the tranlations, when we are obligated to consider the meaning, everything loses sense or sound very un-natural. I find that's why more and more people use these bad words, becouse they are becoming just sounds, quasi non-semantic sounds, that just express rage or anything else.
Forgive my eventual spell errors :)
Wozzeck