Here’s George Orwell discussing the magic and strangeness of swearing in Down and Out in Paris and London:
The whole business of swearing, especially English swearing, is mysterious. Of its very nature swearing is as irrational as magic—indeed, it is a species of magic. But there is also a paradox about it, namely this: Our intention in swearing is to shock and wound, which we do by mentioning something that should be kept secret—usually something to do with the sexual functions. But the strange thing is that when a word is well established as a swear word, it seems to lose its original meaning; that is, it loses the thing that made it into a swear word. A word becomes an oath because it means a certain thing, and, because it has become an oath, it ceases to mean that thing. For example, – – – -. The Londoners do not now use, or very seldom use, this word in its original meaning; it is on their lips from morning till night, but it is a mere expletive and means nothing.