My mother (born 1907) did not swear, nor did my father (born 1912). That was partly a generational thing, partly an aspirational thing: by not swearing you distinguished yourself from those of your neighbours who were "common". Interestingly, the fact that he did not swear did not handicap my father when he resorted to verbal abuse. The invective which he hurled at my mother through much of my childhood was meant to be wounding and he usually chose my mother's most vulnerable side, her history of mental illness. He didn't need swear words, just the usual synonyms for "mad".
As a result of that exposure I have no talent for that kind of invective. If I lose it, as I occasionally do, I do it fairly clumsily. I think of the Bon Mots afterwards.
But as for swearing, it is something I had to learn in the playground. When I was eleven and it came to choosing a Grammar School for me, my mother rejected the local Dartford Grammar School for Boys since she had heard boys wearing its uniform swearing in the street. So she sent me to Bromley Grammar School for Boys with whose local streets she was unfamiliar.
Parental influence probably explains why I don't swear very much. And I don't think I am very good at it. That's a pity, because a well-chosen swear word can help one express strong ocurrent emotions effectively: anger, frustration, irritation, exasperation, surprise, shock, amusement .... Sometimes I try my hand at it, more so now that I am older and my children older. And, of course, social attitudes have changed. It is a job qualification for a politician or a politician's spin doctor to be able to swear like a trooper.
Swearing is an art. Some people do it extremely well. I can think of only one occasion where I felt I did it to perfection.
I had set my MA class of Creative Writing students the task of reading Ted Hughes' Birthday Letters and had picked out certain poems on which to focus. We were looking at a page together, around the table in our evening session, and a student asked me what a certain line meant. I looked down at it. I was probably tired. There was an audible sigh:
They found that very funny (I am sure they had not heard me swear before) and we then had a good discussion of the line and the poem in which it was housed. When I can find the book, I'll post the line here:
But to use expletives well in writing is a different art from the art of swearing. And it's a difficult one. There are two separate branches of the art to be mastered:
(1) Using expletives in dialogue attributed to a character and as part of the characterisation. Here there may be a problem of relying too obviously on stock expletives associated with a particular social group - Cockneys, for example. The problem isn't really specific to expletives: for example, there is a whole vocabulary you can call on to fix a character in the genus, English Public Schoolboy circa whatever date you choose. But after a while spiffing gets tedious.
(2) Using expletives to indicate the emotional state of the speaker or narrator (often, a narrator who is going on at length) or to indicate the attitude the writer takes towards some person or institution or argument - so the problem is not specific to fiction. The problem is this: Swearing occurs - one could say, at its best - in the context of the immediate, unreflected expression of ocurrent emotion. But a writer poised to insert an expletive into a text is not normally undergoing the ocurrent emotion he or she is trying to characterise or express. So the risks of picking the wrong word or putting it in the wrong place are considerable.
The best advice one can give is then identical to that any Creative Writing teacher will give for the use of adjectives in general: Use them sparingly. Or not at all.