I've noticed that pretty much all swear words or profane language contains one or more fricatives, and sometimes plosives.
Without listing words, if you can think of the first ten swear words that come to mind, they will almost invariably contain hard-ts, hard-ks, hard-gs, etc. Even if they're not in English, this is the norm. I've found there are less examples of fricatives/plosives in French profanity, however.
What is the psychology behind fricatives? Are some words offensive strictly because of meaning or also because of linguistics? When we hear a fricative, does our brain have some inclination to believe it's profane? If I make up some fake words containing fricatives, some of them potentially sound obscene, but this is a subjective test.
Obscenities do change over time, with new words coming about quite often, but they almost invariably contain fricatives. Why is this?