Well, the only reason some words are considered "bad" is because most people who speak that language (or dialect) have decided to set those words apart, to classify them as "socially inappropriate". The words themselves, while usually having to do with things that are taboo (such as sex and excretion), are not really considered bad because of that.
If I tell someone to "have sexual intercourse with himself" he'll just laugh. If I tell him to "go fuck himself" things are bound to get more interesting.
I don't see anything wrong with that, expletives are born for a reason. The
method by (through) which they are chosen is a little unreasonable, yes, but the same could be said for practically anything that relies on the decision of the many.
People need short, concise words that carry negative connotations, and when there's a need, society provides.
Imagine you are walking down the street and some fucker throws a milkshake at you from a moving car. You don't know who he is, what offends him, your time is limited and you're really, really angry. What would you do?
If people didn't get offended by certain words, you'd be fucked.
We agree up to this point. Expletives are good.
You have, however, defended:
A)The use of expletives in fiction.
and
B)The "cleverness" (I'm using this word because I'm too goddamn lazy to think of one that's more appropriate) of cursing.
I don't think the use of expletives should become widespread in fiction. If it did, we would soon become completely desensitized to them, they'd stop being considered "offensive enough" and we'd have to come up with new ones. Since the new ones would be promptly used in fiction on a massive scale, those new swear-words would become harmless too, and we would have to come up with
new new ones. And the cycle would repeat itself on an on, the birth and death of new insults going on at an ever increasingly fast rate. While this "life-cycle of expletives" itself is nothing new, the lack of "predators" (concerned mothers, old people with too much free time, most of the religious right (for some reason), etc...) would completely destabilize the rhythm at which new insults are born, it wouldn't give them time to "mature", to fully develop all those interesting variations that make them so goddamn funny. Take "fuck", for example. Have you ever read the word's history? It goes back way before the romans. That's about two thousand years. No wonder it is such a beautifully versatile word, it has had a long time to mature, like a fine wine.
Wanna know what happens when the lifecycle of shit get all mixed up (and shit)?
Everything turns to feces! (and shit)
Even without taking that into account, expletives are just too simple, unimaginative and unoriginal to earn the respect of an intelligent reader/audience/listener. But that has more to do with my second point:
People who swear a lot tend to be fucking stupid (self-loathing is fun!). Why?
Because swearing is simple, it's the standardized way to insult people, and the almost exclusive use of them to insult others reveals an appalling lack of ingenuity in the offender. Every person is different, everyone has his own buttons, things that really hit the very core of his being. Thing that kick that little child we all have inside right in the face.
A truly personalized insult requires thought, elaboration, subtlety.
A simple "Fuck you" just won't do.
If, on the other hand, you were thinking of expletives as a form of adding emphasis, well, I recommend reading this:
http://tvtropes.org/pmwiki/pmwiki.php/Main/ClusterFBomb
http://tvtropes.org/pmwiki/pmwiki.php/M ... ionFStrike
P.S. I find the mere suggestion that I might be anything other than human to be extremely offensive. In fact, my human feelings are so hurt I'll now react in a pointlessly violent, probably counterproductive way, as we humans always do. Then I'll probably put a piece of breadcrumbs-covered avian muscle in my human mouth, and move my single-jointed mandibles up and down to cut it into smaller pieces, because my human digestive system, which is not pathetically underdeveloped, can't absorb them otherwise. Then my brain will practically stop functioning for about 9 hours for no apparent reason while I lay defenseless in a piece of cloth. Good (human) times!