Prospero peruses the subject:
Taboo words can survive underlying social change. Church attendance has plummeted over the past few decades in Quebec, but a distinctive clutch of swear-words in the local variety of French are still some of the roughest words in the language: chalice (calisse!) and “host” (hosti), for example. The words remain powerfully charged partly because they are simply learnt as taboo words, and serve a special function divorced from their original context.
Swearing activates a bit of the brain that is used for other kinds of emotional responses like shouting and crying. The reason it is so hard not to swear in front of a child when you stub your toe is that you haven’t consciously processed the words through the same part of the language engine that you would use to explain a maths problem. Studies have even shown that swearing makes physical pain more bearable. …
A last class of words, though not quite as powerful, fill out the picture.