"Why do you say Brooklyn is shit?" he asked, perplexed.
"Not shit. The shit. The difference is, you see, the shit is really-really good, and shit is really-really bad. Do you understand?"
I smiled listening to it. Curse words never have a good answer for "why." You just learn what they mean and use them when you're angry or upset. But, being just words, why do they insult us so much and why we often feel uneasy when hearing them?
I personally noticed that obscene words of another language do not insult me as much as the foul speech of my own language, and I don't like teaching people bad Russian words. Not that I don't know them or don't ever use them. I just feel that they are reserved for certain situations and should not be dropped around in vain. Therefore, the first reason why curse words are so disturbing is because they create the effect of shock on people who hear them. However, if used often enough, they lose their "magic power."
Second of all, it is the purpose of using the words that shakes us most. People swear when they hate or disrespect someone, or when their patience reaches its limits. Think about it: if you're really angry at your parents or your teachers, you are not likely to curse them out because you feel their authority and do not want to show disrespect, whereas when talking to your friends or acquaintances, you feel more comfortable and might use a word or two. It used to be considered impolite to swear in front of "a lady" (any woman, basically), and I still appreciate when people apologize to me if they said something inappropriate.
Third of all, if we look into the nature of many "bad words," we can see that many deal with religion. God damn, for instance, or hell. If we look into the origin of the word profanity, we can see that it is literally translated from Latin profanus as 'before (outside) the temple,' meaning 'desecrating what is holy,' according to Wikipedia. In other words, they first appeared as the expression of blasphemy - the words that were unacceptable to use. And even though we no longer make that connection, we still feel that there's something wrong with using them.
And finally, the society has strong associations, stereotypes, if you wish, with people using curse words in their everyday life. We don't expect a professor to use foul language, while a truck driver is almost expected to drop "an f-bomb" here and there. We think that it has something to do with education and the way the person is brought up, or with his or her politeness. Thus, when we hear a nasty word, we right away make an assumption that the person who said the word lacks culture.
And nevertheless, profane words are just words, and they are an important part of our language. It is not accidental that people create euphemisms to replace "bad words" - we need them to express the boiling point of our emotions. However, we must always remember that there are other people around us, and that by using inappropriate language we might offend them or leave an impression contrary to the one we would like to leave.