Why do humans find it amusing to cuss?

This is something that I have always wondered, mostly because of high school students. I remember way back in the day (elementary school) where if someone said "shut up" everyone else responded with an "OOOOO she said a bad wooorddd!!!" All of the sudden in high school though, its okay to drop the f bomb every other word. Why does that change happen in our life? When did it suddenly become okay for us to use crude words? If we aren't allowed to say something when we are young, what makes it okay to say it when we "mature"? How are we being "mature" when we use language like that? All these questions come from words that can honestly be offensive to certain people! So why do people insist on using them?! Okay, I get it, sometimes when in a chaotic situation your first instinct might be to yell a bad word, but when you are talking about where to sit do you really need to say the "f word"? I had a teacher once say that people actually use them as stress relief, that it actually makes you feel better to say them. I personally belief that that is not true. There was a time where I myself became very frustrated and yelled a word that I will not repeat on here, and it didn't make me feel better! No! It made me feel much worse! So worse in fact that I burst into tears! It didn't help at all! So can someone really use the excuse that it helped them feel better? When in the first place, the "bad words" that people use didn't originally present them selves as grotesque language. They used to mean poop, sex, female dog, black person, etc. So when you get mad, why all the sudden must you have a need to yell a word that means sex? Really? If you stub your toe are you really going to grab it and jump around going "Poop poop poop!" No. That doesn't make sense! Then why do students call each other these crude names as if its funny? "You're a female dog!" "hahaha" ??? WHYYY!! It's rude! Whats the point of it? Then when you ask someone to please not cuss, and instead of being polite they say ten cuss words in a row? Why? Why must you do this?! Are there any other words in your vocabulary?! I don't understand. But I do LOVE the people who are completely respectful, and when you ask them not to cuss, they don't! Or when someone accidentally cusses they say sorry! If you are one of these people, just know that I love you! So, this question is remained completely unsolved for now. Maybe one day I'll understand, or maybe not.