"I curse the day you were born"

Cursing. Where exactly did curse words, bad words, cusswords, etc. come from? I mean I know where mother fu**er came from but what about the other words? What kind of reflection does cursing really have on a person? I mean I'm a 26 year old African-American male that doesn't curse and I know I'm an oddity, but I don't feel fully comfortable around someone until they curse around me. I don't really think any less of the person if they curse once every other day or once every other word. Does it matter? I was once told that cursing was a sign of a lack of intelligence but isn't a just a way of showing emotion? I mean in saying, "This is hot" and in saying "This shit is hot" you can perceieve the difference even without punctuation. You can generalize and say that an upper-echelon of people don't use profanities and to this I say is that do they not use them or is it that they don't use them in an area that will allow them to be judged as a lower class or not smart enough to have a word to fit? I guess this is a debate that can go on forever so I say fuck it.